Vrisha

Krishna to Arjuna

O sinless one, I swear to thee that hero is still incapable of being slain by anybody else save thee. 

1. Devoted to Brahmanas, 
2. truthful in speech, 
3. engaged in penances, 
4. observant of vows, 
5. kind even unto foes, for these reasons Karna is called Vrisha.