Discord and the Unbinding of Lackluster

(Loosely based on a roleplay from Discord. Cut me some slack)

Argon is an engineer who works day in and day out, toiling on machines whose purposes he doesn't dare to question.
William is a poet, translating mountains of ancient texts and strange runes full of hellish terrors that he dismisses as fiction.
Hymn is a world-renown composer and conductor, and has been called upon to play a song she's never heard on instruments she's never laid eyes on.
Dr. Penny Jekyll is a famous scientist, overshadowed by her record for tampering with dangerous forces.

Bound together by Dr. Jekyll's dangerous experiments, the four find themselves in the midst of a terrible war, one that has raged on for centuries- and one that could mean the end for life as they know it.