Legendary

I know about unique but what does legendary on a card mean

You can only have 1 card with legendary in a whole deck. So for example if you put a tangath toborn general in your deck you can't use another tangath general or another diffrent legendary card like the hornsabre at all in that deck.

Working of what he said, you can still put in another Tangath-you can have 1 legendary, but it doesn't have the "unique" restriction.
Unless I'm wrong and I'm just forgetting things.

Quite correct bobo legendary doesnt care abou the cards name only if any other card also legendary (of course the rule of two still applies of they share a name of course.)

They did this because the only cards that are legendary are the 4 generals and the 5 Tribe battlegear. Since the battlegear are loyal I don't know why they're legenday too.. like Hornsabre is Loyal to overworlders and the only legenday overworlder is Tangath OG who would be practically useless in a same tribe deck. The reason they made Legendary is so you dont make a deck with the 4 generals together. Tangath OG and The mipedian general would be crazy good.