In HtC, the 3rd level of Primarch's Curse for the Space Sharks says they keep to themselves and generate no cohesion/are always in solo mode. RAW implies that a Carcharodon Kill Marine cannot use his special ability of one man squad mode. As a GM, would you allow him to still use this ability?

Probably not still allow it. Primarch's Curse level 3 is supposed to be on the line of unplayability after all. Shouldn't have gained all that IP.

Yup, seems pretty definate. Primarchs curses can do some annoying things.

Gaining that many IPs for a space marine is hard. He has to really work at it.

Ok, excellent. It was more of a concern of should they take the specialty knowing that enough insanity loses it for you. But, if that high insanity isn't really a common problem, then there shouldn't be an issue. Thanks guys!

He can take Kill-Marine at Rank 1. Primarch's Curse shouldn't usually be hitting level 3 until the endgame, if ever.