三人行，必有我师(焉)

成语
冷酷无情, cold-hearted and unfeeling (lit. cold, cruel, without feeling)
网开一面, lenient, to give an opponent a way out (lit. to open one side of the net, going back to the Xia Dynasty)*
秋后算账, to settle the score at a suitable time (lit. to settle accounts after autumn; accounts seem to vary on whether prisoners were executed in autumn or farmers did their books after harvest)
( pinyin )
*It looks like if anyone wants to study Chinese idioms in Japanese through Nirvana in Fire, you can do that here!

词汇
只, only; 只能, can only; 只要, as long as (pinyin in tags)
https://mandarinbean.com/new-hsk-2-word-list/

Guardian:
看来黑袍使大人并不像他看上去那么冷酷无情, it seems the Lord Envoy isn't as cold-hearted as he appears
怎么就对咱们老大网开一面, no way is he going to show leniency to our boss
该不会是秋后算账吧, isn't he just waiting for the right time to settle accounts?
只要你多看多听多学，你自然就懂的多了, as long as you see, hear, and learn a lot, you will naturally come to understand more

Me:
别说不能吃巧克力，这么冷酷无情啊。
这样的规则的话，我们只能看样子。