yes, only EN. It's one of the prizes for winning the War

Oh, and one queston more, the containers doesn't have an expire time, do they?

Thanks for the info! So you recommend me to rank up to WO1 before oppening the containers?

I have a question, if I don't open my containers and I rank up, the rewards of the container will be better? Or they will remain with the rewards for the rank I was when I received them?