Did a bunch of class A marks this morning. You can do as many as you want. Class B gave me 5 marks 30 mythology and 10 soldiery. Class A gave me 20 marks 80 mythology and 20 soldiery. I already have over 100 marks. I'm assuming Class S have a long spawn timer similar to Odin and Behemoth while B is shorter and A is medium. Happy hunting.