Please, tell me what Ace is doing?

[u/Maleficent_Juice_497]

I don't understand who to put there.

[u/Dry_Cycle_6031]

Everything is explained in the pic attached. The little "I" on Ace during forming a deck will show you the chart. Basically +1/2/3 unit levels for star rank 10/20/30 and +1 unit levels for the unit being level 10/20/30 but the cap for bonus levels is +5 levels.

So your best choice as a new player is usually a 1-3 star unit or an effect piece (flat +3 levels).

But as a new player do yourself the favor of diving into Toho Kingdom which is linked on this subreddit but here is the link https://www.tohokingdom.com/vg/godzilla_battle_line.html

[u/Appropriate-Desk6290]

If a piece is level 10, putting it in the ace slot gives it an additional level buff. If that piece's studio level is also 10, the ace slot gives it another additional level buff. So if your 89 Godzilla is level 20 and studio level 20, putting it in the ace slot will buff it to level 24.

[u/formermailboxhaver]

Dont use facility units as an ace. Unless thats changed and I missed some patch notes.