When did Ronnie Sukiart appear in the Baccano! anime series?

So in the anime Baccano! he appears in his human form only twice, but it isn't until the end of the show that you know it's him (I think it's episode 16 it's revealed). As for the Celty question it doesn’t come up in the anime (and she dosn't make an appearince in the Baccano! anime), so it probably happens in the light novels. Both Baccano! and Durarara!! are written by the same author and take place in the same universe.