Gammamon

Its Gammamon, make big boi sirius. I don't run lvl 7 because 1) He needs arcturusmon in order to have a reasonable cost, and only way to put arcturusmon under sirius is to wait until you have arcturus before you go into sirius, which is slower and hurts deck space. 2) He is only arguably better than sirius with gammas under him, cuz sirius can unsuspend himself giving him the similar ability to get rid of sec without staying suspended, and sirius can consistently pop every turn using raid/piercing combo (they are both at 4). . 3) Usually leaving sirius unsuspended and with evade is enough to keep him alive.  Gulus most of the time isn't neccessary and you would rather have any other gamma, and we don't really need the extra searches from his deletion effect.