nihiloi asked: Is the Commader Ob Nixilis card before he went to Zenidkar, or after the hedron was removed on Duel of the Planeswalkers?

Ob Nixilis of the Black Oath represents him from a long time ago. This card confirms ol’ Nixi was human once. (Not a very nice human, but human.) So this was him before he got de-sparked on Zendikar — and before he became a demon.

So the sequence is:

Ob Nixilis, planeswalker and extremely unkind person, roams the Multiverse.

Becomes a demon at some point, possibly in relation to some kind of less-than-virtuous oath.

He comes to Zendikar centuries ago, lured by its powerful mana. He encounters difficulties with said local mana; has his spark fragmented. Loses ability to planeswalk. Is seriously grumpy.

http://magic.wizards.com/en/articles/archive/ur/dreams-damned-2014-08-06

Becomes further disempowered when someone called Nahiri fuses a small binding hedron into his forehead. Loses even his ability to fly. Insult is added to injury. Becomes even grumpier.

Centuries pass. Other planeswalkers meddle. Eye of Ugin opens. Eldrazi rise.

Later, during the events of Duels of the Planeswalkers 2015, the hedron is removed from Ob Nixilis’s forehead so that it can be used to keep the cursed planeswalker-hunter Garruk from gaining any more dark power. The spread of Garruk’s curse is halted, for now.

Now freed from the binding hedron, Ob Nixilis has regained his wings – but not his spark. He remains on Zendikar, studying the power of the hedrons around him, cultivating a growing list of grudges.

Ob Nixilis: Career jerkface.