Special Summon 1 "Orcust" monster from your Deck, except "Orcust Harp Horror", also you cannot Special Summon for the rest of this turn, except DARK monsters
When paired with tokens or graveyard recursion, this is an incredibly impactful ability that can repeatedly put an end to most threats on the board
Discover Summon Limit from RA01 set
The adorable Sazh's Chocobo is the perfect turn-1 play, Its also a great target for Traveling Chocobos top-of-library casting ability (being a Bird spell) and doubles its counter gains with Traveling Chocobos trigger-doubling
Aggro vs Control An aggro deck will try to win the game as fast as possible by attacking early with creatures
There are plenty of toolbox ways to misuse this, from slotting it into dedicated reanimator shells to looping Gray Merchant of Asphodel for continuous drains