Suggestion is an enchantment that imposes the caster’s will on the mind of its target; it bends desire rather than matter. During the descent through the Inferno it played a central part in breaking the company apart.
Adam, the harlequin avatar, cast it on Bertrand to force him to give up the lantern. Bertrand resisted twice and yielded twice. When the bond tying him to the lantern was undone, he also lost part of his hope. The company split after that act, and hope waned in all who descended.
Michel was also compelled by a suggestion, on the day of the false Master.