How to get last artifact??
places to find the artifacts:
-one from each boss (so 3 from bosses)
one from kasumi (blue haired girl in Fortune cat) after beating her in the Coliseum. (you can find her after giving the kaiser the jewel that you get after beating the metal ruins boss).
one from Isabel (blonde girl in the Coliseum) after beating her in the Coliseum (tho you'll need to finish her side quests)
Side quests for Isabel:
1- after beating the first boss, go to the Coliseum and fight the boss there, then go sleep and come back to the Coliseum, see the tv screen and talk to her, there will be a a being (the guy that runs the shop) to your left, talk to it and go to the alley at night to the upper floor to see her giving a bj.
2- after beating the 2nd boss and beating him again in the Coliseum, do the same as the first time, this time they'll tell you that she is working in the 2nd floor (Note: you need high lewdity of 40 at least to be able to go to the 2nd inn floor to see her).
3- somewhere in the lost labyrinth (or metal ruins) you'll unlock a door using one of the 3 keys and get a "recording device" you go and take it to the shop keeper in the 2nd floor of the "shop" area , then go sleep for a day and go to the Coliseum to find Isabel talking with the same being(the shop keeper) talk to him again or go and sleep for a day and then talk to him (no diffrence just not sure if you can talk to him right away) he'll ask you for 10k , offer it to him and then go to the shop area and there will be a vid playing on the tv screen near the shop.
4- now you can go to the Coliseum and talk to Isabel, you'll be able to find her in the Coliseum menu, now all you have to do is fight her and win, she'll give you the last artifact(might wanna lose once if you want to get your loosing scene in the "extra" option in main menu.
once you have the 5 relics go to kaiser and talk to him, accept to fight the last boss and either let him hit you to get 2 scenes , or simply win and finish the game.