He's a five color commander who cares about sagas: so much so that he caused price spikes for recently printed sagas, from fans keen to build a deck with him at the helm
Most GB decks are generically just called rock decks however there are vast numbers of ways to build the deck due to the fantastic depth and strength of the guild
Othelm, Sigardian Outcast / Mike, the Dungeon Master Graveyard recursion is more for black decks, but Selesnya decks can have some synergy with that as well with Othelm, Sigardian Outcast
When you cast Leviathan, you can remove four Card Name Leviathan in your Break Zone
In cube with Divining Top, Brainstorm and other blue library manipulation this dork is pretty easy to flip
Rowan, Scion of War is a cEDH level card with a much easier condition to fulfil (losing life) and access to X-spells that actually end the game