Created by Chris Claremont and John Byrne in Marvel Team-Up #68, D'Spayre is one of the Fear Lords -- beings of immense power who target the souls of others. Created by the Dweller-in-Darkness, D'Spayre is a particularly cruel member of their order. Capable of mystical telepathy, D'Spayre causes horror and despair in his victims, so as to feed off the negative emotions that well up inside of them.
He's nigh-unstoppable on the physical plane, and has come up against a number of heroes over the years -- with the heroes often tasked to overcome their greatest inner demons to defeat him. One of the most impressive examples of this though came at the hands of Cyclops, the long-time leader of the X-Men, who confronted D'Spayre in the aftermath of one of his greatest losses.
In the aftermath of Jean Grey's apparent death during the events of the Dark Phoenix Saga, Scott Summers elected to leave the X-Men for a time. He briefly found a new life as a fisherman, making friends with the locals and developing a skill for simple work. In Uncanny X-Men #144 by Chris Claremont and Brent Anderson, he is invited to keep his new friend Lee Forrester company as she goes to visit her father, Jock. Unbeknownst to her, Jock had recently taken his own life at the prodding of D'Spayre -- who had then turned its attention onto the nearby Man-Thing and defeated it. Luring Cyclops and Lee to the swamp where Jock committed suicide, D'Spayre soon dragged them into his realm and throwing them through visions of loss and pain.
Cyclops is forced to confront his past in a series, where his memories are shifted and alter and take dark turns -- including a lethal attack on the X-Men that resulted in the twisted deaths of all his (then former) teammates, as well as a strange and ethereal near wedding to Jean -- that ended with Scott accidentally killing Jean with an optic blast. D'Spayre gloated over the hero and his grief, prompting Cyclops to rush out a near window and nearly fall to his death. But Cyclops refused to give in, picking himself up and deciding to fight back against the villain. Racing after Man-Thing and finding him engaged in battle with D'Spayre, Cyclops was able to defend Lee.
Although his optic blasts could do little to harm D'Spayre, Cyclops was able to gain control of his fears -- removing the innate power D'Spayre had used against him. While D'Spayre gloats that nothing Cyclops can do will even slow him down, Cyclops instead just tackles the Fear Lord and calls him out, daring him to strike him down. Scott's show of courage is enough to inspire Man-Thing and strengthen his own resolve, allowing him to attack D'Spayre and turn the tide of the battle. Meanwhile, Scott used the opportunity to save Lee from the collapsing building as it became engulfed in flames.
Ultimately, the mystical natures of Man-Thing and D'Spayre kept them from suffering any long term repercussions from their encounter with Cyclops. It's still a minor but noble victory for Summers, especially so soon after the loss of Jean Grey. It's a good reminder that even though there are mystical and cosmic forces technically beyond the physical realm and the capabilities of their powers, its the mettle of the heroes themselves that often prove to be the key to winning the day in the Marvel Universe.