I have this idea about Art the Clown

My theory is that he was a family doctor or a high risk pregnancy Dr, and he saw both Jonathon and Sienna being born then something happened.

Something happens where the power shuts off or otherwise short fuses the electricity onto his body; scrambles his brain making him demented and amnesiac to his own identity. Essentially a new creature with old skillsets and memory

He sees the drawings left in the hospital room, Michael Shaw completed after the dreams he, "hadn't been himself".

Could this be the demon entity in whole or partially to at least some extent Art along with Victoria Heyes? I personally think the plot is arranging to seemingly Controls some aspects of what supernatural elements are at play and play in on why in T4.. Perhaps someone did a blood curse/pact and sacrificed them in a deal with a demon who's now coming to collect.

Which is why after the final fight in movie one the lights flash back on when Art murders the Morgue Dr. At the end of T 1 to start, you know, really living his best...

after life