He has many, but the one he has most often is of coming out of stage 3 and finding he's killed his new family too alone again. Or maybe worse, that he'll never quite be without someone from his past.
Luckily, it is just a nightmare, and he has a different Nightmare he can see to help him calm down.
Imagine being Cross, thinking he's so cool and mysterious for staying with someone outside of the castle for a night and not telling them about it and then he gets to Epic's house in the omega timeline and he's like "hey man, one of my roommates is hanging with his friend with benefits or whatever, I hope you don't mind" and it's fucking Killer
where is all the century of love fic? I went on ao3 and there was nothinggggg! nothing!!!!
where are the fics about fox demon!vee and san fucking nasty?? where's the fics exploring how san felt watching friend after friend die as he lived on?? where's the hurt/comfort fics of San going with Vee to visit his grandmothers grave??
where's the fics where Vee finally seduces that old man and rides him into the sunset "what was better, dream me or the real me?" where's the fics where San embarrassingly buys a wig for Vee to wear and live out some fox demon roleplay?
where's the fics diverging from canon where the shady ass uncle finds the "real" Vad and Vee was actually a backup and now San has to choose between the man he's been falling in love with and the idealized reincarnation of the woman he loved a 100 years ago!?