Keep an eye on your ability use rate. Arduin is most powerful when you make use of Undying Protector to buff your normal attacks in conjunction with the healing abilities of Bloodlust.
What you need to know about Arena of Valor new hero abilities, story, attributes, and more.
Dire Blow makes Astrid immune to all damage, which is invaluable when she has low HP. This allows Astrid to deal heavy damage and stun enemies while running to safety.