The original Mandalorians were a reptilian and war-like species called the Tong.
However, they began to die out. It probably had something to do with the constant warfare and it couldn’t have been easy to get little Miss Mando interested in you without at least a little peek under the helmet. Okay, I’m not sure about the helmet thing but…
The desire for the culture to continue led to the Mandalorians accepting other species into their society. To walk the way of the Mandalore became a creed, a religion, and not a specific race or species.
By the time of Mandalore the Great, humans had mostly replaced the other people.
Tar Vizsla was not only the ruler of the Mandalorians, he was also a Jedi. He created the Darksaber and ruled his people. After his death, the Darksaber became a symbol of the right to rule.
So, who is the rightful heir to the Darksaber now? I submit my opinion that it belongs in the hands of a Mandalorian Jedi. A tiny, little, green, and reptilian one.
Bin Djarin, son of Dinn Djarin, founder of the Mudhorn Clan of the Mandalorians, to be precise. He will definitely be strong enough to become both a Mandalorian and a Jedi.
So, there you go! The true Heir to the Darksaber. I have spoken.