So, let's say Ive had a 0/3 otyugh on the field for 3 turns. If I use Accumulation it would add 3 turns worth of defense (0/6). It is acumulative, so the next turn I use it again, the otyugh has been in the field for 4 turns so it adds 4 turns worth of defense (0/10). Next turn (0/15),(0/21), and in seven turns i can turn my armagio into an otyugh.