The first bloodline Erik received from Elora was the Raiju bloodline, granting him a lightning affinity and a boost in physical strength. It took him a full seven years to fully integrate this bloodline, as he was barely a first-rank at the time and Elora was still learning his genetic makeup.
After arriving on Earth, Elora offered him a choice: continue with the Winter Wolf bloodline, for ice affinity and increased endurance, or the Bakaneko bloodline, for shadow affinity and enhanced speed and agility.
In the end, he chose the Winter Wolf for its future benefits. Now, he was glad he did, as it allowed him to develop the thundersnow affinity. He hadn't missed the added speed and agility so far, especially since his new spatial affinity compensated for his relatively low speed.
Which meant that, in order to compete with Frostfang, Erik was most in need of agility and strength.