This is the cast type skill for rift spells.

The in game help reads:

Skill duration: random.
Type of skill : spell casting skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
This skill lays the groundwork for all spells which manipulate cross-dimensional
energies, and beings. Even the most accomplished Riftwalker does not disregard
the knowledge gained from these simple, but foundation-forming abilities. The
guild has a saying "Disregard the simple, and simple you shall remain".