User blog comment:DYBAD/Character Sheet/@comment-24696772-20160412120441/@comment-4867780-20160417061501

Lawrence was created on a transfictional basis, with the Prime Undefineness being ultimately the origin of all multi/omniverses, and him the only surviving shard that later gained sentience through absorption/merging with the first human being. The rest of it simply ceased to exist when it "emerged into defined existence", creating the aforementioned multi/omniverses through spontaneous evolution, and losing its Prime Undefineness (un)quality in the process.

The infinitesimal shard that eventually became Lawrence survived due to an immanente fundamental flaw : the inability for spontaneous evolution the rest of it had, that allowed the genesis of the infinte diversity of multi/omniverses. Due to this inability, the shard's original purity was retained, and while it cannot truly "become" something else, it can use this purity to claim any existence/phenomenon into itself and temporarily emulate its attributes (until the next shifting).

Sorry for getting sidetracked, couldn't resist the opportunity to explain it again ^ ^; (last time was quite a while ago). To answer your question, Lawrence cannot return to his "original plane" because it was forever lost with the genesis of everything else, and Lawrence himself is its sole legacy, the only proof that it ever existed.