This might be nearly ten years too late. But it is possible to use extreme cheesy goodness to be a Warlock 1 / Anima Mage 10 / Ur-priest 2 / Mystic Theurge 7
This character would end up with the invoking of an 18th-level warlock (dark invocations), the spellcasting of a 9th-level ur-priest (9th-level divine spells), and the pact-making of a 10th-level binder (a pair of 6th-level vestiges assuming you take Improved Binding)
6th-level vestiges allows you to pick Zceryll, the Star Spawn. And fun fact, the *free* Summon Monster spell you can cast once every 5 rounds is not keyed off your binder level. The text says "You can summon any creature from the summon monster list that a sorcerer of your level could summon" so spam Summon Monster IX, and that creature gets the pseudonatural template applied to it for free... And so do you.
Also since we complete anima mage entirely we get vestige casting, i.e. the ability to cast a spell as if Still and Silent and as an immediate action! Interrupting any action by any character.
To get in to Anima Mage early you need to use the two feats from flaws to get Bind Vestige and Improved Bind Vestige from Tome of Magic. This gives us the ability to bind a single vestige, which grants only a single power, as a 5th-level binder. That allows us to eliminate the level of binder altogether.
Thus, entry into Warlock 1/Anima Mage is entirely possible, and absurdly, it advances us as if we were taking binder levels even though we have none to begin with.
If retraining or psychic reformation is available, our Warlock 1/Anima Mage 2 can take Improved Binding and safely ditch Bind Vestige and Improved Bind Vestige.
This build drops Hellfire Warlock, which would be great to pick up in epic (especially since you can certainly bind Naberius)
This was posted to Stack Exchange at
https://rpg.stackexchange.com/quest...level-casting-warlock-invocations-and-binding
By the amazingly good KRyan
https://rpg.stackexchange.com/users/4563/kryan
Some alterations were made.