Part of the Sea of Conquest Heroes Series:

Heroes Hub: Slots, stars and roles (Start Here).

SP Heroes: The other limited-window tier.

Hero Tier List: Where collabs rank.

Conches and Summoning: Saving for a banner.

Quick Answer

Sea of Conquest runs crossover collaborations on roughly a yearly August rhythm, and the confirmed ones are:

Collab	Heroes	Ran
The King of Fighters XV	Mai Shiranui, B. Jenet	August 2025
Onimusha	Onimusha (Cutthroat First Mate)	Season 3
Fist of the North Star	Kenshiro, Mamiya	August 2026

No collaboration has been documented as rerunning. Treat every window as your only chance.

And the cost is the part nobody mentions: one creator estimated roughly $1,000 to take a KOF collab hero to 12 stars. Obtaining a collab hero and building one are entirely different projects, and a low-star collab hero loses to a maxed accessible one.

The Trap With Collab Heroes

Collab heroes get enormous attention because people recognise the franchise. Mai Shiranui and B. Jenet both landed in S tier, and that is genuinely earned — but rank them by the same criteria as everyone else, not by nostalgia.

The governing rule has not changed: a 6-star Epic beats a 2-star Legendary. A collab hero you pull once and cannot progress is a 2-star Legendary with a famous name.

Before you spend saved currency:

Does this hero fill a role you actually lack? If your Cutthroat seat is covered, Onimusha is a sidegrade you cannot afford.

Can you reach meaningful stars? Collab shards vanish when the window closes. If the answer is "I can pull once," the honest answer is do not.

Will you still field them next season? Broad kits age well; narrow ones do not — see the seasons guide.

The Heroes

Mai Shiranui and B. Jenet (KOF XV, August 2025) both rank S tier. The collab also came with a dedicated gift code, 2025SOCKOFXV, long since expired — see the codes guide.

Onimusha (Season 3) is a Cutthroat First Mate, and one of the heroes specifically recommended for Trials alongside Kartal and Bones — single-target burst that removes a threat before it acts. He also has an exclusive trinket granting critical rate, which is usually a hero's best gear slot.

Kenshiro and Mamiya (Fist of the North Star, August 2026) are the newest arrivals, announced through the official YouTube channel. Servers open 7 or more days were eligible.

Planning for the Next One

Given the August pattern, the sensible approach:

Watch the announcement, not the launch. Collabs are announced ahead of time. That is when to start saving conches — see the conches and summoning guide.

Decide before the banner goes live. Once it is running, the pressure to pull is real, and pulling on an unplanned hero is how saved currency evaporates.

Bank free shards regardless. Event side-tracks and login campaigns hand out collab shards during the window. Take everything free even if you will not finish the hero — partial progress banks against a future rerun.

Check the official channels for the codes that cluster around collab launches: the official Discord (around 216,000 members, with code channels), the official X account and YouTube.

Are They Worth It?

Yes if: the hero fills an empty role, you have banked currency specifically for this, and you can reach meaningful stars.

No if: you would be spending general savings for a low-star result. Put that into Cursed Ed, Old Ahab or your existing core instead — all of which you can actually finish.

The uncomfortable maths: $1,000 to 12-star a collab hero, against zero to max a farmable Epic that never leaves your formation. For most accounts that comparison settles it.

FAQ

Do Sea of Conquest collabs rerun?

None has been documented as rerunning. Treat each window as final.

What collabs has Sea of Conquest had?

KOF XV (Mai Shiranui, B. Jenet) in August 2025, Onimusha in Season 3, and Fist of the North Star (Kenshiro, Mamiya) in August 2026.

Are collab heroes better than normal heroes?

At equal stars, often. At realistically achievable stars, usually not — collab shards disappear with the window.

How much does it cost to max a collab hero?

One creator estimated around $1,000 to reach 12 stars on a KOF collab hero.

Should free players chase collab heroes?

Collect the free shards, but do not spend saved currency for a low-star result.

When is the next collab likely?

The pattern so far is roughly annual, around August. Watch the official Discord and YouTube for announcements.

Key Takeaways

KOF XV, Onimusha and Fist of the North Star are the confirmed collabs.
None has rerun. Every window is your only chance.
~$1,000 to 12-star a collab hero. Obtaining ≠ building.
Decide at announcement, before banner pressure hits.
A maxed farmable Epic beats a 2-star collab Legendary.

Sea of Conquest Collab Heroes: KOF, Onimusha and Fist of the North Star