Whenever one or more Assassins you control deal combat damage to a player, exile up to one target Assassin card or card with freerunning from your graveyard
You can't attack with them the same turn you play them, unless they have haste
White control decks almost always include blue cards, creating the most complete array of defensive abilities possible in Magic
If you want to only discard one card it has to be a basic land, but the inability to discard nonbasics is minor when coupled with the bump from sorcery to instant
There are, however, two things you should know about the back faces of these cards
With that in mind, the second Commander option is Inspirit, Flagship Vessel