Unlike other strategy games, Ultimatum focuses on units being able to advance in levels, and become stronger as they receive battle experience.

Like any other game with an experience system, a unit will level up when its experience reaches or exceeds its max experience. When a level 1 unit levels up, the skill that has been used the most (successfully hit the most times) will level up, and its damage will increase by 1. The unit's maximum health and mana will also increase.* There is also a probability that the unit's movement points will increase by one. Remember that units may only level up when it is your turn, so a unit can be killed during the time when it gets its maximum experience, and when it is your turn. Units that level up will also have their upkeep increase. If a level 2 unit levels up, they will be able to upgrade to another type of unit.

Every odd level, a unit will be able to upgrade (if there is an upgrade unit available). If a unit has one upgrade type, the unit will automatically upgrade when it is your turn. A unit that has upgrade when it was your turn will not be able to attack or move until your next turn. However, if a unit can upgrade to two or more units, an upgrade menu will pop up when you start your turn.

In this menu, you can pick what type of unit you want your advancing unit to upgrade to. The upgraded unit will take your better stats, and all of the new skills. The unit will take the same traits as the previous unit, and will fully heal in health, mana, and supplies.

Most units have up to 2 to 3 upgrade levels with the exception of some special units. Some units don't even have upgrade levels. Units can level up until level 10, where they will not level up anymore.