The Ultimate Last War Survival Season 4 Week 4 Guide: Copper War, Atomic Breath & Tenryu Castle

Week 4 switches the season from growth to contested territory. All five main missions are visible from Day 1 except the Level 7 city mission, which starts on Day 7. Warbreaker, Ruinstriker, and Warlord track Copper War participation directly, while Trade Baron and the Tenryu Castle capture reward alliances that keep working the map between battles.

The chest goals are warzone-wide, so your personal contribution matters less than showing up: every commander who joins rallies pushes the shared counter. The mission goal for Trade Baron and the Level 7 city unlocks 12 hours after the mission appears, but the reward-chest goals are trackable immediately.

The Copper War is an alliance-versus-alliance war between the two Week 3 factions, Kage no Sato and Koubutai. There are eight rounds in total, two per week from Week 4 through Week 7. In Week 4, Kage no Sato attacks first while Koubutai defends first, and the roles swap every round — by the end of the season each faction has attacked four times and defended four times.

The objective is Copper, not territory. Attackers who destroy buildings around a defending Alliance Center plunder a percentage of that alliance's stored Copper: each of the three warehouses is worth 3% and the Center itself adds 6%, for a maximum of 15% per war. That cap is a meaningful reduction from Season 3, so wars are about consistent, well-targeted raids rather than one snowball victory.

Two Season 4 rule changes shape every fight: Alliance Centers may only have three secondary buildings (the Stone, Oil, and Magatama Warehouses), and declaration brackets split into narrower rank groups every week, forcing similarly sized alliances to fight each other as the season progresses.

Every round follows the same multi-day structure, twice per week. Copper totals are recorded at the Monday (and Thursday) reset and define the ranking brackets you must declare within. R4+ of the attacking faction declares war on Tuesday (and Friday): one target at a time, only inside the same Copper ranking group, with up to three alliances able to pile onto a single defender. The target can be changed until the stage ends, so declarations are a commitment window, not a coin flip.

On Wednesday (and Saturday), the invitation stage gives defenders 12 hours to call in same-faction allies from the same ranking group who are not already declared upon. Three attackers allow two defense partners; two attackers allow one. The invited alliance's R3 members vote, and the partnership locks once accepted.

Preparation begins at 12:00 server time and lasts 30 minutes: the war is confirmed, the Alliance Center cannot be changed, and both faction skills can be launched. The battle itself starts at 12:30 server time and lasts 20–40 minutes depending on the matchup. After the war, an end-of-war stage runs until the next 0:00 reset, when unclaimed rewards are mailed and ruins auto-rebuild if R4 does not rebuild them.

War length and defender rewards scale with the matchup. Even fights (1v1, 2v2, 3v3) last 40 minutes. When attackers outnumber defenders, the war shortens but outnumbered defenders earn multiplied victory rewards: 30 minutes at x2 for 2v1 and 3v2, and 20 minutes at x3 for 3v1. If the battle timer expires with the Center still standing, the defense wins.

The defending Alliance Center has 200,000 durability and garrisons up to 100 defending squads; each of the three warehouses has 50,000 durability and its own 100-squad garrison. Defenders must actively reinforce every building they intend to protect — an empty garrison melts to rallies. Center durability does not regenerate during the war, the Center cannot be relocated mid-war, and if the Center is at 0 durability or was never built when the war starts, the defense is lost automatically.

Attackers should clear warehouses before touching the Center: destroying the Center ends the war immediately and does not auto-destroy the remaining warehouses. Note that you can loot Copper while technically losing — any building destroyed pays out its percentage even if the Center survives. Among multiple attacking alliances, loot is split by each alliance's share of durability damage.

Watch your own exposure when attacking: hitting the Alliance Center drops your shield, while joining rallies does not — so structure attacks as rallies whenever possible. Attackers' Centers need no territory connection, and defense partners' troops do not clash with each other.

Two war-only skills are tied to named alliance official positions, and both can be launched during the preparation phase — you do not have to wait for the battle window. The attacking alliance's Warlord wields Atomic Breath, a re-skinned Warlord's Missile. It devastates a 35×35 area: every base in the radius is forcibly relocated (shields are not broken), and any Alliance Center or warehouse caught in the blast takes 30,000 durability damage. The struck zone becomes Contaminated Land for one hour.

Atomic Breath has a 180-second launch window during which the Warlord's base location is announced in world chat and can be attacked. If the Warlord's base moves or drops to 0 durability before launch, the shot fails and the skill goes on a 72-hour cooldown. Use it to open jump-in spots next to the enemy Center, to scatter their garrison bases, or to delete a key warehouse's durability before the first rally — and remember the Week 4 season mission explicitly asks you to fire it.

The defending alliance's Butler controls the Tesla Coil, which replaces Season 3's Mummy's Army. Deployed on any alliance building, it adds 50,000 durability and shocks enemies in a 21×21 area every 10 seconds for 500 damage, lasting up to 300 seconds or until destroyed, on a 72-hour cooldown. The Butler stays safely shielded while operating it, Electricians on the building boost its damage, and the alliance tech that illuminates the path adds a further 10%.

A proven defensive timing from Season 4 veterans: fire the Tesla Coil about five minutes before the battle starts if attackers have already grabbed prime tiles in your territory — the damage plus the durability buffer often convinces light attackers to relocate before the real fight begins.

The City Clash ladder finishes on Day 7 of Week 4, when the Level 7 city, Tenryu Castle — the season's Capitol — unlocks 12 hours after reset. Capturing it is the Week 4 'City Ready for War, Level 7' mission, and it is the one map objective of the week that is not a faction war.

Tenryu Castle is worth the fight for more than the mission. The Capitol does not count against your alliance's six-city limit, so it is a free seventh hold, and it anchors end-season play: alliances need territory adjacent to the Capitol — a city or Digging Stronghold works — to join the Week 7 Faction Duel and the Week 8 Capitol Conquest, where the Capitol is worth 10,000,000 faction Copper and each of its three giant cannons adds 6,500,000.

Standard City Clash rules apply: your alliance needs a connected territory path, one city target at a time, and a maximum of two city war declarations per day. Sieges kill a percentage of the garrison outright, so bring full marches and expect losses. Once captured, a city enters a protection period of roughly six days, and abandoning it does not reset that timer — plan your grabs before rivals do.

One warning carried over from earlier weeks: a captured city's buffs stay locked until your alliance defeats the Oni General that besieges it during a Blood Night Descend. If you take Tenryu Castle or any high-level city this week, schedule a rally for its Oni General at the next 02:30, 10:30, or 18:30 server descent.

The Trade Baron mission wants the warzone's Trade Post Lords to collect 300,000 in tax revenue, so the Tuesday and Friday Trade Post contests now feed directly into a season reward chest. The rotation from Week 3 continues: posts open for contest at 12:00 server time on both days, with one hour of competition, and the Level 3 and Level 4 posts remain the high-value targets for weapon shards, Training Certificates, and Overlord materials.

Holding a Trade Post pays the Lord in Copper tax — which doubles as Copper War fuel, since recorded Copper decides your declaration bracket every Monday and Thursday. The Governor should still base on the Contaminated Land adjacent to the post to unlock restocking, purchase discounts, Golden Egg taxes, and the Magatama Trade Caravan during Blood Night.

If you took the Trade Discount profession skill, the 10% post discount stacks with this week's mission push — restock immediately after each contest while prices are reduced.

Blood Night Descend continues three times per day at 02:30, 10:30, and 18:30 server time, 30 minutes each. Week 4 sits inside Stage 3, 'Doomsday Crisis: Oni Legions' (Weeks 3–7): Blood Night Oni Legions — Doom Walkers — spawn across the map and prioritize attacking bases with their lights on, while monster Virus Resistance rises by 500 and base corrosion adds 500 Commander Durability Damage against breached bases.

Stage 3 is also the best Magatama and Tactics Card farming window of the season. The Oni Summon profession skill lures an Oni Legion to you for five minutes, chaining kills into big Magatama and Tactics Card Fragment payouts, and Tactics Card Pack drop rates rise by 30% during descents — up to five cards per day. Keep the Lighthouse on Brightness Auto-Adjustment: full-brightness drain climbs to 18,000 per minute, and even Level 1 light makes your base immune to active attacks.

Do not skip descents if you hold cities this week. Oni Generals besiege owned cities during Blood Night, and until your alliance kills the General, the city's buffs stay locked. Rally them immediately after each capture — Tenryu Castle included.

The profession cap is Level 100, and both professions — Engineer and War Leader — share the same seasonal skill tree, so war week is about which skills you buy, not which profession label you carry. Four war-phase unlocks deserve your points now that the Copper War has started.

Lightfall (Level 70) keeps a breached base's lighthouse extinguished for three minutes, stripping its light immunity while your alliance chews through its durability. Disruption Mine (Level 75) plants a mine that stops enemies from relighting for three minutes for a full day. Oni Summon (Level 80) doubles as a Blood Night farming tool and a way to pull Legions off your territory. And Summon Mummies (Level 85) — widely considered the must-have — summons a 37.5-million-power mummy boss that marches for 30 minutes, deals 10,000 durability damage when it breaks a base, and forces even shielded strongholds to react. It requires Protector's Field Level 25 and only one skill point.

Free-to-play players should treat Summon Mummies as the goal to reach before Copper War rounds 3–8, when declarations narrow to three-alliance brackets and every bit of siege pressure counts. Above Level 100, profession EXP converts into core Tactics Card upgrades, so keep farming EXP through the war weeks.

Copper War pays on three layers. Victory rewards are claimed through the event interface, with the outnumbered-defender multipliers (x2 and x3) applied on top. Individual war points — earned from kills, losses, and healing — unlock milestone chests as the war progresses; community trackers place the thresholds around 50,000, 200,000, and 500,000 points, paying Honor Points, Stone, training items, and speedups. When multiple alliances attack the same target, rewards follow each alliance's ranking of Center durability damage.

Honor Points deserve a special note for Week 8 planning: attacking the Capitol — or fighting in the mud area around it — converts troops killed or lost into Honor Points. That is a long-way-off payout, but the habit of joining every war round this week is what keeps your personal totals climbing.

Everything unclaimed when the end-of-war stage closes at the next 0:00 reset is mailed automatically, and ruins rebuild themselves if R4 does not get to them — so a missed claim is never a lost reward, only a delayed one.

Week 4 sets the template for the rest of the season, so build a repeatable rhythm rather than a one-off push. Monday: bank Copper before reset and review the ranking snapshot. Tuesday: agree declaration targets in leadership chat and set rally timings. Wednesday: reinforce every warehouse before 12:00, launch or answer the faction skill during preparation, and fight at 12:30. The same loop repeats Thursday through Saturday, and Day 7 belongs to Tenryu Castle and Blood Night farming.

Between wars, keep the economy loops that fund everything else: Lighthouse upgrades and Brightness Auto-Adjustment, the Trade Post contests on Tuesday and Friday, daily Blood Night descents for Magatama and Tactics Cards, and steady profession-tree progress toward Summon Mummies. Save seasonal resources for the second half — Williams' Exclusive Weapon Battle Pass arrives in Week 6, and the Faction Duel and Capitol Conquest close the season in Weeks 7 and 8.

Skip nothing: unlike daily events, a missed Copper War round is gone forever, and the chest goals behind Warbreaker, Ruinstriker, and Warlord only move while the warzone fights.