Dominus litis is the person to whom a suit belongs. This also means master of a suit. The person has real interest in the decision of a case. It is this person who will be affected by the decision in a case. This person derives benefits if the judgment is in favor, or suffers the consequences of an adverse decision.
A person can be dominus litis even if his/her name does not appear in a case proceedings as a petitioner or defendant. This person will be liable for the expenses incurred if the person under cover of whom this person was litigating defaults in the payment.