One of Team Umizoomi's allies in the episode "Journey to Numberland".
Her gender is female.
Also, a related Wiki to Dragons.
However, at first she was not an ally. She was first encountered on Pattern Peak when Milli and Zilch raced to the top for the Heart Key. Zilch created her as a grumpy dragon from magic to stop Milli from keeping up with him. But Milli, as we know, would not let anything stop her. But with her pattern powers, she got the dragon less grumpy and gave her a good laugh.
The Dragon, as thanks for the good laugh, gave Milli a dragon ride up the mountain, and she was able to get the Heart Key before Zilch could grab it. Milli and the Dragon flew down the mountain and had Geo and Bot hop on the Dragon as well. The Dragon flew Team Umizoomi back to Numberland while seeing the lions and Square Beard along the way. When they got to the Crooked Tower where the King of Numbers is trapped, the Dragon let them hop off. Then, as she flew back to Pattern Peak, she wished them good luck as parting words.