Alexander_the_grey
Perseus definitely has a lot potential he’s not only son of Poseidon but also Descendent of Zeus , so he should have lot potential specially when MC helps him awaken his bloodline and awaken more of his talent like for example His control on Lightning should definitely be high ( blood of Zeus and Poseidon) , control and Manipulate Water and cause Earthquakes ( Blood of Poseidon) control Lightning and Wind ( from being Descendent of Zeus ) and also unlock more of his swordsmanship talent to highest lvl Basically Perseus will definitely be powerful Satan/God Class being and MC might get him a Scare Gear because him being half human
you should have medusa eventually become a lover/wife and have medusa lancer(child) be there daughter. plus with how the story is going she could become a knight for sona (similar to how ravel became a bishop for razer) and look up to sona as a big sister of sorts (especially since I could see serafall dragging the mc around when she learns about magical girl)
Also with perseus assuming he trains ideally under lith and has his potential unlocked their are several paths he could take to be Satan class he can gain the other specializations later maybe like lith is doing bit these are the paths I see: 1. Water path: my preferred one cause I also somewhat like pjo Percy. Also if by Canon he is Satan class he can be sonas teacher. 2. Ice path: a possibility though sera peerage already has an ice path. 3.earth path. 4. Tremor path: think whiteboard in one piece. 5. Acid path: altering the waters ph. 6. Weapon path. Plus with a Pegasus ranch maybe Sergil will gain his own horse harem and start making little Alison's. after all in dxd power as well as looks are very attractive and whats more attractive to horses then a ultimate or is he a Satan class yet unicorn with enhance space abilities