Note the mana value of each card as it's put into exile.

Bell Borca, Spectral Sergeant's power is equal to the greatest number noted for it this turn.

At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Flying

Whenever a creature card is put into an opponent's graveyard from anywhere, you may pay life equal to its mana value. If you do, put it onto the battlefield under your control. It's a Warlock in addition to its other types.

If a Warlock you control would die, exile it instead.

Trample

Whenever another creature dies, put a +1/+1 counter on Orca, Siege Demon.

When Orca dies, it deals damage equal to its power divided as you choose among any number of targets.