Ally in Chinese / Japanese...

アリー is the name Ally in Japanese.

Note: Because this title is entirely Japanese Katakana, it should be written by a Japanese calligrapher.

阿利 is the name Ally in Chinese (Mandarin).

盟友 means a sworn friend or ally. If you stand on the same side of an issue with someone and perhaps fight for the same cause together, this is the term you would use to describe such a partner.

There may not be a personal relationship, as this term is also used to describe whole countries that make a coalition or fight against a common enemy.

This would be most appropriate if you are a high-level military officer, giving this wall scroll to an officer of another country as you join forces together and go to war.