Y'shtola gives you a second end step, which includes a second free blink every turn
Odric fit into the deck because hes a Soldier and the deck has enough individual creatures with the abilities that he shares to be worthwhile
This 4/5 Dino boasts Enrage, allowing you to draw a card whenever it takes damage, whether that be via a spell, via combat damage, or any other way this feisty beast might get pinged, such as via 15
The trouble with demons is that theyre so expensive, so the best way to play with demons in EDH has always been to cheat a few in with a Krrik, Son of Yawgmoth deck or some kind of Shadowborn Apostle structure
A guarantee of making your next land and a bit of board development
The reason this is so highly rated is that he fits so well into the meta rather than being of incredible power or even from having incredible support