For other meanings, see Level.

When you first acquire a lieutenant, they have a level of 1. If they are in the right hand position of your inner circle, they will gain experience as you fight bosses, undertake jobs and engage in PvP battles. When they have gained sufficient experience, they will gain a level. This increases their attack and defense by 1 each.

Each lieutenant has a maximum level they can reach, which is determined by their rarity and their star rating (see Star (Lieutenant) for the details).