Tom Rune Andersen (born 18 October 1976), also known by his stage name Galder, is a Norwegian guitarist and vocalist.

He is a founding member of the melodic black metal band Old Man's Child[1] as well as the lead guitarist of Dimmu Borgir from 2000 to 2024.

[2] In 1993, under the stage name Grusom, he, Jardar, and Tjodalv created Old Man's Child.

[3] A member of Dødheimsgard, Aldrahn, wrote some of the lyrics for Old Man's Child's demo album In the Shades of Life.

Galder has two sons, Alex and Kevin, who are listed in the credits of Slaves of the World.