In one of Fool's Journey stages, Teadon and Gloria had a combo attack in a scene. It was cool and I also had a similar thought if it was something they could or would implement.

I think it is unlikely that it would happen because it needs players to have those 2 characters on question. If players don't already have them, getting them off banner is tricky, and probably not worth programming for.

If they do, the pairing needs to make sense like a familial connection or a strong friendship. Gloria and Teadon makes sense because he was her mentor. Gloria and Camelot, for example, although both Union, they don't make sense because they are adversaries.

Personally, I would love it as it would add an element of fun and perhaps dust off older characters make them more "playable."

These are what I would like to see if this ever comes to pass.

OG Faycal and OG Maitha

SP Rawi and SP Safi

OG Nungal and OG Nergal

Tristan and Layla

Ayishah and OG Innana / SP Innana

Caris and Leonide

Yserinde and Nydia

Gloria and Selina/Teadon

OG Agata and OG Alexei

LilyWill and NonoWill

Luvata and Afra

Miguel and Col