Brother Henri

Brother Henri is a member of the Church of the Children of Atom in 2287.

Background
Brother Henri was sent to the Sentinel site, a nuclear launch site located in the Glowing Sea, by Mother Isolde to claim the various atomic weapons stored there. Despite being the Sole Survivor of his group after his fellow cultists were massacred by feral ghouls, he continues to guard the main bomb storage with support from a machine gun turret and Atom's Wrath, a named but otherwise normal Assaultron.

Other interactions
Henri is one of the very few Children of Atom in the Commonwealth that don't attack on sight. While more or less friendly when first encountered by the Sole Survivor during the latter's mission to secure the Sentinel site's Mark 28 stockpile for the Brotherhood of Steel, he is quick to anger when not taken seriously. Heaping scorn on his overblown religious zealousness will result in him "invoking Atom's Wrath upon the Survivor", turning him and his robotic protectors hostile and leading to a fight in extremely close quarters. Doing so will displease many of the more well-intentioned companions like Piper or Curie while most of the others tend to be indifferent about it.

Conversely, passing an easy charisma check allows the Survivor to convince Henri that they share his point of view. In this case he will freely hand over his terminal password which is required to open the gate to the bomb storage, thus avoiding having to fight him and his Assaultron altogether. It is unknown what happens to him once the Brotherhood arrives to evacuate the warheads he is protecting with religious fervour. Considering both factions' uncompromising bigotry and the Brotherhood's massively superior firepower and numbers, it probably doesn't end well for Henri.

If you have joined the Children of Atom at the Nucleus in Far Harbor, you may tell him this. Henri will be in awe of you and allow you to pass, not wanting to hold up your "pilgrimage."

Appearances
Brother Henri appears only in Fallout 4.