What shell i do with me yu gi oh deck?

Yeah umm Jonathan this is my Pera Bobic but useing friends mail because i forgot my email on yahoo so..it doesnt matter but one question....why take out Phantom Beast Rock Lizard???He has 2200 for attack and when he destroys a monster or attacks directly you take damage plus 500 and when he is destroyed be effect of card and sent o the graveyard you opponent takes 2000 damage...i am just saying..and yeah a just got Exodia The Dark Master what should I do With it because he is DARK atribute????