A player loses the game after having been dealt 21 combat damage from any one of them, not from both of them combined (although your Background wont usually be a creature anyway)
In hindsight, I think there were a couple reasons I felt like this
Commander Masters' Sliver Swarm preconstructed deck will offer newcomers to Magic: The Gathering a quick and easy way to grab one of Commander's most venerable strategies
And I've been having a lot of fun on MTG Arena, collecting via jamming drafts instead of (on MTGO) playing a handful of drafts and then collecting via trading/buying, as I used to do
4 Ghyrson Starn, Kelermorph (Surge Foil) - $49.35 Ghyrson Starn, Kelermorph is the sparkmages king, upgrading all your one damage spells and abilities into three damage
You can also get cheeky and add Curiosity effects and go for a combo-kill with Brallin