the cthulhu thing is based on how much validity you put in the chinese version of the game since its a cn-exclusive story. as for the baby trapping... thing is tsukasa is so loyal to the rest of his unit (his base card is literally called Leader of Loyalty) that ritsu wouldnt Need to resort to that..... but ritsu is very possessive so i could see him purposefully getting pregnant with tsukasa's kid just to show off that kasa is his. alternatively he could use his alchemy to get tsukasa pregantn,