Set 18 of Teamfight Tactics has a trait that never appears on any champion card: Eclipse. It is a hidden bonus that switches on when your board meets a specific condition. Once active, it removes enemy units on a timer during combat.

This article covers how to trigger it, what it does, how it has performed in Patch 18.4b data, and where the sources disagree.

How Eclipse Is Activated

Eclipse is not a trait you can assign to a champion, and it has no emblem. It comes from combining two visible traits: Solar and Lunar. Fielding 3 Solar champions and 3 Lunar champions at the same time turns it on.

That makes it different from a normal trait, where you stack copies of one trait to reach a breakpoint (a unit-count threshold that unlocks a stronger bonus). Here you are building two trait lines at once, so your board needs to fit both.

  • Solar: 3 champions needed
  • Lunar: 3 champions needed
  • Eclipse: activates automatically when both conditions are met

A Lunar Emblem can supply the third Lunar if you are one champion short. That is the only emblem route, because Eclipse itself cannot be granted by one.

What Eclipse Does in Combat

Eclipse is a delayed execution effect. After a set amount of combat time, it kills the enemy with the lowest current Health. It then repeats on a fixed interval for the rest of the fight.

Most trackers list an 8-second delay and a 3.5-second repeat. Under those numbers, a long fight produces kills at these timestamps:

  • 8 seconds
  • 11.5 seconds
  • 15 seconds
  • 18.5 seconds
  • 22 seconds

Because it targets the lowest-Health enemy, it tends to finish off wounded units, including backline carries that your team has already damaged. It does not do anything in the first seconds of a fight, so your board has to survive that long.

Why the Numbers Differ

Sources do not agree on the exact values. Several pages list an 8-second delay. Others list 10 seconds, and one lists a 4-second repeat instead of 3.5. Patch 18.4b was a mid-patch update released on October 7, 2026, and a community post refers to an Eclipse buff in that update. Some pages may therefore reflect different versions.

The official Patch 18.4 notes returned in research do not spell out an Eclipse change. Check the in-game tooltip for the current numbers rather than relying on a third-party site.

How It Plays in Practice

The community guidance is consistent: build a board that survives long enough for Eclipse to start working. A fight where you are wiped in the first few seconds never benefits from it.

One guide describes a level-6 reroll approach built around 3-star Leona, Kayle and Sejuani, then adds Diana and Aphelios. In that line, a Lunar Emblem provides the third Lunar.

A Reddit post titled Don't Reroll Solar in patch 18.4b argues for a different path after the Eclipse buff:

  • Hold an upgraded early-game board.
  • Roll at level 8 for Aphelios and Amumu.
  • Go to level 9 for Alune.
  • Use a Lunar Emblem to activate Eclipse at level 8 without needing to find Alune.

These are player strategies, not official recommendations, and they may shift as the patch settles.

What the Data Shows

The numbers vary by site and filter. One tracker reports 40,452 games with Eclipse active in Patch 18.4b data updated on October 13, 2026. Of those, 25,677 were Diamond+ games. Its Diamond+ breakpoint figures were a 3.57 average placement, a 67.4% Top 4 rate and a 20.9% win rate.

Another tracker, TFT Ninja, reports Eclipse active on 1.7% of boards, with an average placement of 3.49. A rate that low shows it is not a common outcome. Win rates for rarely reached states can also be skewed, because players who hit a hidden bonus are often ahead already.

One site also notes that no published comp is built around Eclipse yet. It is more of a bonus that some lines can reach than a set-defining strategy.

Limitations and Open Questions

  • Conflicting values: the delay (8 vs 10 seconds) and repeat timing (3.5 vs 4 seconds) differ across sources.
  • Dual requirement: you need three champions from each of two traits, which constrains board choices.
  • Survival dependency: it does nothing if you lose the fight early.
  • Unclear raw values: one data table lists a damage threshold of 7,500, but the sources do not explain how it is used.

Conclusion

Eclipse is a hidden payoff for pairing 3 Solar with 3 Lunar champions. It kills the lowest-Health enemy after a delay, then repeats every few seconds, rewarding boards that last into the later part of a fight.

Early Patch 18.4b statistics look promising, but timing details and data are still inconsistent between sites. Verify the numbers in game, and treat reroll plans built around it as experimental until a clear comp emerges.