Odion's highest defense monster is a Giant Axe Mummy with 2000 Def. However, it can't do anything after you special summon your Gate Guardian. You can check more details and information regarding the deck by clicking the link below!
Summon the unhappy girl, or rai-mei if you don't have her, and pass the turns to stall the duel until you can perform the gravekeeper vassal and union attack combo. Once you summon the unhappy girl, set rai-mei again once you have enchanted javelin to raise your LP. This will make sure Odion won't attack, otherwise pumpking with castle of illusions to deal more than 5000 damage with 3 monsters.
I used the already mentioned Dino farming deck against Odion about 7 times now. I figured I'd try to farm LD's since there's the 1k bonus currently. I've only lost 1 of the 7 duels (only managed to draw one monster early). I'm able to average 6,100 - 6,400 with this deck (7,100 - 7,400 with current 1k bonus). I highly recommend the deck.
The fusion weapons are for the fusion monster that isn't shown but there are two in this deck. It's the monster that combines two headed king Rex and crawling dragon number 2. It's called brachiradius or whatever. It's a 6 star monster, so you end up putting both fusion weapons on it and at the end of the duel you use it to inflict the "over 5,000 damage" for extra assessment points.