Thats a lot of cards for not a lot of mana, but it is color heavy
Pillar Analysis: High Power (Dual Land), Scarcity (Beta, Reserved List), Format Staple (EDH/Vintage)
It enters with +1/+1 counters and mills cards based on what you paid, helping load your graveyard
I used EDHREC's Average Deck function to grab a quick sample of a Multani, Yavimayas AvatarMultani, Yavimayas Avatar deck from EDHREC to use as a starting point
Im still up in the air on whether I go through with that build, now that weve seen all the cards, or just jam Kethek into one of those two decks
But be aware- in true Pokmon Company style- there have been times when the Weakness & Resistance rules changed: 2007 to 2009 (Diamond & Pearl, Platinum)