Another suggestion: Expanded sewers under new ark. Remaining on the standard path to enter the slums works as normal but there is a secret path (not visual obvious but can pass through a narrow path) through the sewer water (entering sewer water tiles adds the filthy debuff if not already present which reduces all attributes by 20% - they sewer water is a long way from clean so want to have a shower to clear the debuff, which functions like the slime effect). The sewer area consist of 4 to 6 rooms and using the sense skill at high enough level will reveal some containers (one per 'room') with unique clothing (unique for this play through - only unique effects is the higher then average sell value, the appearance (leave the art to someone better - maybe some alternate art versions of clothing already present ?) and after finding all the items a optional challenge NPC will show up (defaults to male but also has a female variant - only a visual and description change). This character takes on the form of a rugged looking man or woman (crocodile / alligator with furry NPC's enabled) with a large body, flat chest and large penis if male or a loose pussy if female. Character stats are very high strength & resistance and a natural 50% reduction in weapon damage (fists, magic and lust damage work as normal). Losing to them causes the PC to black out and wake up at the entrance to the secret path with 1 health, beating them gives the option to have sex with them (genital / anal).
Should it be a Crocodile/Alligator, let its Unique attack be a Death Roll, basically a charged attack that Grapples you and Charges in 2 Moves, failing to escape could Damage your Stamina with a Massive amount.
But we already have a Gruff, Violent, and Possibly, toxic relationship which might be Arlene... so making a Character heavily based of how they act in real life might work better.
Shy, Quick, Effective, and Likes Groups but Disallows Relationships.
They are social, but Aromantic,they group up, has high tolerance but will still attempt to gain a bit of Isolation.
You are more or less thinking the same was as I was when I had the idea - I was inclined to leave the actual artistic elements and writing to people better at it but I was thinking along the lines of rugged in so far as some visible scars / healed injury's on the chest and arms and only wearing something like a kilt and belt but topless (character has a flat chest so could be mistaken as guy even they are female if you don't look to closely). As for the personality of the character I was thinking reserved until you demonstrate enough strength to beat them then they reveal they are shy and kind of cute, with a preference to a more gentle sexual partner.