Soul Power Edit
Main article: Soul Power
Once the first step is taken is learning to manipulate one's soul, the only commonly available method to grow stronger is time. While a device like the Magic Shield can be used to provide enhancements to a servant's soul power in a limited manner, even this advantage requires the servant to have a minimum age in order to use this boost safely for a meaningful length of time.
Soul power provides numerous advantages, such as making manifestations of a power more effective and more resilient, restricting an enemy's use of their own ability through field density and making the servant themselves more difficult to hurt through passive soul defense. All of these become more effective as the reaper and servant's souls become more synchronized.
Use of the Shards of the Dry God may or may not accelerate a servant's natural growth in soul power, but access to the shards is limited and their use weakens a servant's ability in the short term, making their use a risk.
Servant Ability Edit
Main article: Servant powers
The older a servant gets, the more time they will have to both develop their ability and discover new uses for it. This growth is not fixed like soul power, however. It requires the servant to practice meditation, train with their ability or achieve emergence. This means that if a servant did not work to improve their ability, its growth would be slowed dramatically if not stopped entirely. However, a servant who trained intensely or achieved frequent emergence (like Hector) could become far stronger than other servants of their age.
Though servants can fight effectively using only their own powers, there are still several reasons why having large amounts of money, contact networks, or conventional weapons can still prove useful. To this end, servants can spend their time gaining wealth and making both servant and human allies. Doing so can provide intelligence, ensure that food and well-hidden lodgings are available, and generally ensure that the servant is able to fight at full effectiveness.