Yep, terrible design indeed. I used all gems and got zero legendaries. And you can't even obtain more gems. But this is a demo; hopefully this is addressed in the soon-to-be full game.

第一个消息的翻译

"你好，
我开始玩这个游戏是在一个可以很容易买到角色的版本（The Brave），然后这个演示版本（The Brave Beginning）出来，我感到害怕：需要宝石来购买角色。

这个‘功能’在游戏的其他版本中不存在，它极其类似于那些以5%的几率诱惑你购买酷炫角色的FTP游戏……并配有相应的商店。

It feels like a cash-shop/lootbox game with new character additions, over and over. We'll quickly find out at the release: whether the feedback has been listened to or if the team has focused on adding characters to increase potential purchases.

这感觉像是一个带有不断新加入角色的现金商店/战利品箱游戏。一旦游戏发布，我们很快就会知道：是反馈得到了倾听，还是团队专注于增加角色以提高可能的购买。

Funny, I came to ask about the same exact thing and saw this post. This design is what they would do if they were planning to implement MTX and turn the game into P2W. The writing's on the wall already, especially with the free to play period right now. I really hope I'm wrong.