This tag should be used for any question that's about the Soldier class from Team Fortress 2, Valve's free-to-play team-based multiplier shooter.
The Soldier is TF2's beginner-friendly class, with high health and an easily-understood arsenal of a destructive rocket launcher with lengthy reload time and a shotgun for more consistent bursts of damage. Though friendly to new players, the Soldier possesses a very high skill ceiling, with his ubiquitous rocket jumps and juggling capabilities.
While not the middle of the road statistics-wise - possessing the second-highest health and second-slowest footspeed - the Soldier is considered a very well-rounded class, with strong offensive and defensive capabilities. Soldiers typically make up the brunt of a team's fighting force and are never a detriment - no one will ever say "we need less Soldiers".