Sadly, I can't host or join the game, but if you are going evil, I have a good build suggestion. Instead of doing cleric/master of shrouds, try cleric/dread necro/true necro. (Naturally, you won't be able to get to true necro until HOTU, so you might just try a straight dread necro build for the OC, then add cleric/true necro for HOTU. (However, since the DN is an arcane caster, you would need someone else to be the cleric.)
If I recall correctly, the master of shrouds undead work well at middle levels but would be very underpowered for HOTU.
Dread necromancers don't look formidable at first: low hit points, low BAB, very restrictive spell list), but with the multisummon switch set to 1 (turned on), a dn can build a fairly effective undead army even at low levels. As the character advances, it can summon creatures up through level 20 (bone warriors, who typically get summoned in groups of three). DNs gradually accumulate resistances and immunities, until level 20, at which point a DN becomes a lich for free (all the regular undead immunities plus immunity to cold and electricity, boosts in several skills, boosts in charisma, intelligence, and wisdom). Also, unlike normal arcane casters, DNs can rebuke undead like an evil cleric. As a practical matter, that means that if you are low on undead and on summon spells, you can use turn undead to recruit any wandering undead into your army.
You need five cleric levels added to the DN to qualify for true necromancer. The TN gives you some additional powerful summons, but the best part is that the TN can create a zone of desecration around himself to strengthens all nearby undead. The level 20 DN, being undead himself, is also strengthened. (Great synergy there!) TN progresses the DN caster level but also adds the cleric levels for any necromantic spell, so that you can end up a level 40 caster for most of your arcane spells. TN turn undead levels also stack with your other turn undead levels, so you can turn undead at level 40 as well. (I'm not 100% sure about the last part. The TN levels stack with the cleric levels, but, since the DN was written later, the TN description doesn't make it clear whether the TN and DN turn undead levels stack.)
Be sure to take Corpsecrafter and some of the related feats, because they make your undead stronger. In particular, I like "chilling touch," or whatever it is called, that enables the undead to do 1d6 cold damage in addition to their normal damages. "Nimble bones," which causes all your undead to move faster, is another must have. (UNnlike a typical arcane caster, you rely less on wreaking direct mayhem with spellcasting, except necromantically, and more on wreaking indirect havoc through summoned undead.
It is true that a DN would be in trouble in a combat situation surrounded by many foes, but with 20 to 30 undead around him, it is pretty hard for hostiles to close in.
Anyway, that's my vote for the best evil arcane build.
