Zanroar

Zanror is Kevdak's son and Grog's cousin. Although initially a member of the Herd of Storms, Zanror later became a prisoner and ultimately the new Thunderlord of the Herd. As an NPC, he is played by Matthew Mercer.

Background
According to Grog, Zanror regularly challenged him to fights in their youth, resulting in Grog regularly beating up Zanror and causing a long-standing grudge between them.

When Grog sought to protect Wilhand Trickfoot from sport-slaughter by the Herd of Storms, Zanror helped several Herd members beat Grog nearly to death. Grog managed to defeat Zanror, but he fell to Kevdak and was assumed dead by Zanror and the Herd. (This event led to Grog's introduction to Pike Trickfoot, who saved his life and healed his wounds.)

Vox Machina encountered Zanror while travelling to Kraghammer (just before the Critical Role stream began). Grog managed to resolve the social encounter without a fight.

Zanror returned to the Herd of Storms and warned them that Grog had survived, but they thought he was lying and beat him.

After the Chroma Conclave attacked Westruun, the other dragons left the city while Umbrasyl, the ancient black dragon, remained. Kevdak swore fealty to Umbrasyl, conquered the city, and provided the dragon with offerings pillaged from Westruun's citizens. Zanror felt that the Herd had become domesticated and tamed by staying in one place so long, and that his father's mind had been corrupted against him by Greenbeard. Zanror plotted a rebellion against his father but was discovered, and Kevdak was warned. Zanror and his pregnant mate, Worra, were put in chains and were awaiting the Herd's version of a "trial" when Vox Machina challenged Kevdak.

Once Grog had killed Kevdak, Zanror and Worra were brought out in chains and Greenbeard tried to persuade Grog to execute them for being weak. Grog acted as though preparing to execute Zanror, then pivoted and killed Greenbeard. Demanding that the Herd of Storms make Zanror their new leader, Grog ordered that Zanror and Worra be unchained. Zanror then told the Herd that they would stay in Westruun for one more night to help slay the dragon, Umbrasyl. Zanror invited Grog and his friends to join them.

Grog
Zanror's relationship with Grog was initially very negative, being one of the people to aid Kevdak's brutal beating of Grog and shunning him from the tribe. It is known that Grog and Vox Machina encountered Zanror at some point on their journey to Kraghammer and whilst it's unknown what excatly happened they parted ways as enemies. Vax was able to help Grog get back up when he was knocked down in The Crucible by yelling "your cousin is going to make you his bitch!" The memory of Zanror filling Grog with rage for his fight. By the time they encountered him again in Westruun it was clear Zanror had changed a significant amount, not agreeing with his father's way of leadership and wanting to slay Umbrasyl which had gotten him arrested. When Grog defeated Kevdak, he decided to make Zanror the new leader of the Herd of Storms. Realising they had common ground in wanting to fight the biggest foe and leave the weak townsfolk in peace, they settled into a more amicable realtionship.