This is Grondas, Kardas dragons brother. Grondas knew that Kardas
had curse what turned him to Fenrakk. When Fenrakk fell to lava Grondas was happy to see his brother normal again, but toas killed Kardas in front of his eyes. Grondas got amazingly high rage against toas.
When toas went to Mahri Nui to look for Mask of Life Grondas followed them to sea. Nobody knows
when Grondas attacks toas.