Octopath x Final Fantasy- the White Mage & Summoner (Patreon)

Currently in 'Champions of the Continent', there's a 'Final Fantasy 4' collab and... cool stuff happens. But there's also a twist to the summonable characters.

Instead of just FF4 characters becoming playable, they've lent their power to existing OT characters. Agnea gets Rosa's. Ophilia gets Rydia's. And Sazantos gets Kain's. It's unique and kinda cool.