Best Multi-colored commander

[Surrogate God]

So I'm kinda stuck on the idea of having an EDH deck of EVERY Legendary Lich/Zombie to make my Undead Army. But I realized the zombie commanders are R/B, R/BL/B, B/BL, and B/G. Only lich i know of that requires any white is Scornful Aether Lich. And Necromancer's Covenant is devastating as well as Rooftop Storm. So the 2 commanders I'm debating over are Reaper King (also in the process of making a scarecrow deck with him and every praetor out there), or Progenitus. Reaper King I'd be fine letting him sit in the command zone like a good lil scarecrow should, but I want a useful commander at times, and that's where Progenitus comes in (granted a hydra avatar doesn't seem to fit in with an army of liches). Scarecrow deck is abit more costly than I'd like, as for the lich deck i have all but 4 legendary zombies. So who would I benefit more in a 5 colored Army of Darkness? I know a majority of this problem is my own personal quirks (and wallet), but any constructive or destructive criticism is welcome, as well as for my current EDH deck I already have made.

[Stego111]

Why not Child of Alara? Progenitus will rarely if ever see the battlefield.

[Arcthos_the_Arcane]

Of the two you listed, I would personally favor Reaper King over Progenitus. He's both more likely to see play and, as a matter of my own taste, more thematically suited (I can see him leading your zombie army much easier than Progenitus). If you want to give him something to play off of, see if you can work some changelings in, and if you're able to fit the five color cyle rings (Ring of Kalonia, Ring of Thune, Ring of Valkas, Ring of Evos Isle, and Ring of Xathrid) you can give him some decent abilities and p/t buffs for a cheap price (mana and wallet).

As for other commanders, Child of Alara has already been mentioned. I would also add Karona, False God and Cromat. I like Karona more from a theme standpoint (a false god bringing darkness instead of salvation), but Cromat has a solid body and a good toolbox of abilities.