User blog comment:GreenMoriyama/Judaeth, Messenger of the Limbo/@comment-22636720-20160713044825/@comment-3391671-20160714044237

The bane of Judaeth's kit: under-explained mechanics =w= (Just to note, I am aware of this and am making a patch for him so that this does not occur)

What type of Mage is he?
 * Judeath is supposed to be a buff Mage, one who utilizes applied buffs to allies or nerfs to enemies to control the battlefield. While he isn't supposed to deal the damage foremost, if he focuses on AP, he can deal a lot of damage with his Q "Dimensional Bullet" coupled with the effects of being in the Limbo. Thus, he can either go bot-Support or be the mid-Mage. In the words of Riot's latest classification, he's a Controller-class Enchanter-subclass. By Willbachbakal's words in his blog, he would be a Support-Sage with a mix of Mage-Warlock/Sorcerer-Hybrid. Hopefully this answer your question.

What is the goal of his gameplay?
 * Compared to other "Enchanters" who apply different kinds of marks on allies/enemies, Judaeth's enchantment (thus his gameplay) is defined by one thing: the Limbo (if that wasn't obvious enough). It's the core enchantment he applies to others, and his abilities change what it applies. He is reliant on taking advantage of it; I don't know about risk, but he is for sure rewarded if he applies the enchantment consistently enough.
 * From a more thematic point of view, he controls an overlapping realm that he can move allies or enemies into or out of. In most cases, it's for the best of him to keep them all in the Limbo to assimilate the full potential of his kit. If he does succeed in this, he is able to buff allies/debuff enemies on a consistant basis if he plays as a support, or clear waves of minions easily while dealing bursts of damage every so and then if he focuses on being a Mage.

Explain the passive.
 * As mentioned before, thematically, Judaeth has access to what is called the Infinite Limbo, an otherworldly plane that overlaps with the "normal realm." Even if you are transferred to this other realm, you will still be able to associate with the "normal realm," but you will be affected by the magical elements the Limbo has to offer. In some way, you become a ghost that is still tangible. In lore, if you are not supposed to be in the Limbo, it will hurt you; if you meant to be in it, you will be enhanced.
 * The passive outlines the basic aspect of the Limbo. Foremost, it provides him a means of entering the Limbo without the aide of abilities (well, without needing Riftwalk), although temporarily. As a "prophet" of the Limbo, he has an advantage (of dealing damage) when in it. Allies to the Limbo are shielded by it, while unwelcomed guests are harmed by its energy, thus these are more static elements that shouldn't be reliant on Judaeth's abilities.

If you have any other questions, please ask. To note, as I mentioned, I'll be making a new patch to take care that these kinds of aspects are explained, along with reworking some of his kit to make more sense of it.