The most powerful warrior.

Red ones don't look as impressive as their Elven counterparts. Elves have a lot of in-game value, and they can also chain their attacks across multiple units. It gets tiring to fight against them!!! From the very first turns, the enemy's troops will start to deal heavy damage... And against ranged units without protection, it's even worse! In my opinion, Crystal ones are much more useful than Red ones.

Added after 4 minutes
Crystal ones are an alternate upgrade for Elven dragons. It's just that the translation in the game is probably not very good.