区别太大了。assemble只是表示组装之类。压力经验的积累用前者

Warriors of the night, assemble!

accumulate是聚集
assemble是组装，合体的意思

【1】accumulate
(1)gradually get more money and knowledge in a period of time
(2)gradually increase the amount and number until there's a large quantity in one place
【3】assemble
（1）come together in one place for a particular purpose 集会
(2)put all the parts together 组装
【2】gather
(1)people come together and form a group;
(2)or get things from different places and put them together in one place
【4】collect
(1)get things of the same type from different places and bring them together
(2)get or keep things of the same type out of interest 收集
（3）get money that you're owed