Transformation of Alastor into a Blue Whale

Prompt: Write the transformation story of Alastor (from an adults cartoon/animated series Hazbin Hotel) turning into a blue whale (scientifically named "Balaenoptera musculus") female from real life, complete with gender change, massive growth, weight gain, body changes (his toothy jaws morphing and developing into a massive baleen-filled jaw, two blowholes on top of his head (formerly his nose on his face), mottled grayish-blue skin (instead of beige skin), a pair of elongated flippers (instead of his arms), small black eyes (instead of his large red eyes), a large tail stock at the root of the wide and thin flukes (his legs turned into a whale tail/fluke), etc), age change, and mind/mental change (with Alastor's personalities and memories being replaced with a female blue whale's personality and memories, with the voice inside his head telling him that he was never Alastor and never a demon to begin with and tells the newly-transformed being that he (now she) was always a blue whale, despite Alastor's understanding of her language and words dimming/shrinking to nothingness, making her completely unable to understand languages or words, making words and language just vibrations/noises to her, and she only knows how to communicate through whale songs and such, before the voice in her head encourages her to mate with the male blue whales to help birth her calf and thus to help populate her species as her kind always had (even her mother, also a blue whale). Despite her best efforts of holding onto the memories and personality as Alastor, she has lost all of them and has completely turned into a blue whale female). For Alastor's appearance, he is a slim, dapper sinner demon with beige-colored skin, and usually has a broad smile full of sharp, yellow teeth. He is approximately 7 feet tall. He sports a pinkish-red cropped, angled bob-cut with black tips at the ends and two large, black tipped tufts of hair extending from the top of his head, evoking the ears of a deer. The style has an undercut at the back, and two small black antlers protruding from the crown, which can grow in size in his full demonic form. Alastor's eyes have dark-red sclerae, bright-red irises and thin black pupils (which can change into the shape of radio dials when shifting into his full demon form). His forearms and lower legs fade to dark grey, and he has red hoofed toes and red fingers. Alastor wears a red pinstripe coat with dark-red lapels piped with white, which is ragged along the bottom hem. Underneath this he wears a bright red dress-shirt with a black cross on the chest, and long black dress pants with matching bright red cuffs. He also wears a dark-red oval-shaped monocle, rimmed with black, over his right eye. He accessorizes with a black knotted bowtie with a bright red center, black gloves with red at the fingertips, and black pointed-toe boots with red deer hoofprints emblazoned on the soles. Alastor also carries a thin cane with a sentient vintage style microphone attached to it, which he uses to play sound effects and broadcast his voice. Alastor stands out from many of the more chaotic residents of hell for his well maintained amiable persona. He gives the first-impression of a good-natured and charming man, wearing a permanently wide grin on his face at all times. Alastor's behavior, mannerisms, and even his voice are similar to an old-fashioned radio announcer and speaks with a transatlantic accent, often using quaint anachronisms such as "the picture show" and refers to Charlie as a "charming demon belle". This playful dandyish exterior, however, obscures a much darker side to him - one with high levels of self-importance - and he will not hesitate to use physical violence when others don't act in line with his very particular values or expectations. For the female blue whale's appearance (after Alastor turned into her), she is 108 feet (33 meters) in length, weighing 173 tonnes (190 short tons), and has a slender body with a broad U-shaped head; thin, elongated flippers; a small 33 centimeter (13 inch) sickle-shaped dorsal fin located close to the tail and a large tail stock at the root of the wide and thin flukes. Her upper jaw is lined with 70–395 black baleen plates. Her throat region has 60–88 grooves which allows the skin to expand during feeding. She has two blowholes that can squirt 9.1–12.2 meters (30–40 feet) up in the air. Her skin has a mottled grayish-blue coloration, appearing blue underwater; her underbelly has lighter pigmentation and can appear yellowish due to diatoms in the water. There should also be quotes from the characters in this story so we know what they're saying and what they're thinking.