King's Proposal Novel Volume 4 was written by Koushi Tachibana with illustrations by Tsunako.

When Anviet saves a mysterious little girl named Surya, the last thing he expected was for her to call him “Papa.” He denies the existence of a daughter, but the news about the discovery of a secret illegitimate child is spreading like wildfire. In the middle of the commotion, Saika appears in black clothes before Mushiki - but isn’t she supposed to be fused with him?