Darksteel introduces the modular keyword mechanic, an ability of some artifact creatures to donate +1/+1 counters when they die (see Mark Rosewater's January 12 column for a full history of the mechanic). Today's Magic Arcana focuses on what, from the creative team's perspective, "really" goes on when a modular creature goes to the graveyard.
First, note that all the creatures with modular in Darksteel are named "Arcbound _______." That gives us a clue to what is going on with these automatons.
Take a look at this picture of Arcbound Reclaimer below. Note how its limbs are floating next to its body, with energy flaring where its joints should be.
Creatures with modular are literally bound together with strands of magical energy instead of mechanical joints. This allows them fantastic flexibility and maneuverability: check out the scary and slippery Arcbound Fiend scrambling along on its arcbound tentacle-rings.
This unique construction also allows arcbound creatures to easily transfer parts from themselves to other artifact creatures. If a removal spell or combat damage manages to sever the electric bonds holding together an Arcbound Bruiser, for example, fear not. Rather than becoming instant scrap, those plates, wires and mechanisms that made up the Bruiser can fuse onto your Razor Golem instead, and continue smashing face.
Plus, having energy-filled gaps between the parts of your body make for some serious offensive potential. Check out this zoomed-in picture of Arcbound Bruiser taking out a pesky humanoid archer! Oh yeah!