Damage dealt additive or multiplicative for Rarhma's1

New to Necro and not sure which of damage dealt skills are A or M? (Rathma’s set)

heard that bane of trapped is Mult and as Krysbin ring is the same… does this mean that together they double my total damage?

how about 1. travelers pledge…double again?
2. syphon blood…10 stacks of 20%…double again?
3. capt crimson
4. bonds of c’lena
5. Jesseta set weapon & shield

cant help but thinking that somethings wrong

really appreciate your help

AlleyOop