Time for another weird one. A compilation of unique bosses from an RPG Maker eroge called Maragon Quest 1. It's a parody of Dragon Quest, where all monsters are girls, which you fight through a sex battle. Aside from the monsters, you can also romance/combat humans. I wasn't sure if I should include the king here due to how childish she looks, but I like her design otherwise, and I tried to visually age her up as much as possible.

The characters included are:

King. She is the one who sends you on a quest to save her daughter (which you never meet, but find out that she's really ugly) and is, according to the game, 33 years old. You can fight her if you lose 15 times, which is basically her training you so you suck less.

King: Maragon, STKing, blonde hair, red eyes, medium hair, small breasts, twintails, two side up

Extra: crown hat, royal dress, white gloves, thighhighs, garter belt, fur trim

Dragon King. She is the final boss (that you can't win against, as she just resets you to before the fight) and is the reason all monsters turned into girls. Typical of JRPGs she also has two forms. It also took me a while to realize that she is wearing a red hat, and her hair is purple in the second form.

Dragon King First Form: Maragon, STRyuo, red hair, red eyes, long hair, medium breasts, tattoos

Dragon King Second Form: Maragon, STRyuo, purple hair, red eyes, long hair, large breasts, purple skin, tattoos, black dragon tail, dragon wings

Extra: black short dress, horned tiara hat, red hat, horns, veil

Demon Knight. She is an optional boss that guards a random village ruins. Not much story there.

Demon Knight: Maragon, DemKnight, black hair, purple eyes, long hair, wavy hair, large breasts, long hair between eyes

Extra: armor, long boots, giant axe

Town Girl. Also known as Puff Puff Girl, she is a girl you can romance in one of early towns and later meet again in a hot spring. She is also not technically fighting you, so your hp will never go below 1.

Town Girl: Maragon, PufPufGirl, brown hair, red eyes, short hair, large breasts

Normal Extra: dress, hairband

Bath Extra: towel on head, naked towel

Revenge Slime. Probably the most interesting boss. She is a self-proclaimed "bad slime" (parody of a friendly slime from Dragon Quest with an iconic "I'm not a bad slime" line), and the first enemy you fight. She also gets obsessed with the protagonist, evolving and coming back for a rematch twice, first time as a red slime, and second as a slime king.

Revenge Slime First Form: Maragon, RevSlim, slime girl, blue hair, long hair, blue eyes, blue skin, medium breasts

Revenge Slime Second Form: Maragon, RevSlim, slime girl, orange hair, long hair, red eyes, pink skin, medium breasts

Revenge Slime Final Form: Maragon, RevSlim, slime girl, blue hair, long hair, blue eyes, blue skin, large breasts, drill hair

Extra: crown, staff, mantle