Obviously Sephiroth, Fabled SOLDIER will be the centerpiece of such a deck
cards are used to pay costs or given to Leaders and Characters to boost their power
You may put a Human creature card from among them onto the battlefield tapped and attacking
Abhorrent Overlord Baron Strucker, HYDRA Overlord Cateran Overlord Extus, Oriq Overlord Hellkite Overlord Hollowhenge Overlord Kobold Overlord Lava-Field Overlord Necron Overlord Nefarox, Overlord of Grixis Overlord of the Balemurk Overlord of the Boilerbilges Overlord of the Floodpits Overlord of the Hauntwoods Overlord of the Mistmoors Rohgahh, Kher Keep Overlord Sliver Overlord Tovolar, Dire Overlord Ultron, Machine Overlord
This game plays essentially identically to the TCG itself, so, once you've gotten your practice with this set, you'll be able to apply your experience to the real thing, though this also gives you everything you need to introduce a new player to the game