Underwater combat problem
You will only get experience for the skills after you defeat monsters, while in DS, and considering how useless DS is underwater, it can be a problem. My suggestion would be to weaken the enemy severely, jump into DS and finish them.
To unlock skill you need to get the last hit with it…
so kill a mob down to almost dead, pop in DS, blast away till its dead, then pop out and fill it up for the next mob
Ah okay thank you for the responses.