All I have right now is a bit of conjecture. Is any of the lore recorded or archived anywhere, or is the story of the tower still an evolving thing?
Ignoring the mechanics for a moment, we've got relics that seek out people who have lost things dear to them, empower them while granting demonic allies, but then urge them to give up whatever it was they were going after to instead enter a death Tower. Within the Tower are countless demons and the remains of failed Summoners, which are sometimes empowered by their Relics to create a Wraith as another test for the living still trying to follow their compulsion. That is assuming the compulsion stays once you enter the tower, though why else are all the other Summoners hostile?
The demons might know something, but they're not the best of conversationalists even if they're surprisingly okay with the whole warlord angle that the Summoners take, and being fused/deleted/etc to further the Summoners cause. We know that Credits are an in-universe thing from Ferret, and there are hints of dialog in negotiations that might help puzzle out why they're important to the demons.
As to the people chained to the walls, that has been clarified to be more than simple a bit of window dressing, which means that it has something to do with who is in control of the various locations of the Tower.
Relics wrote:
- Crown of Glory
Merges with the top of the user's skull, connecting directly with the brain. It seeks those who desire impossible changes.
It is said Crowns of Glory seek those who desire an impossible change...- Eye of the Dragon
Replaces the user's right eye. Finds those who have grasped what they could not hold.
It is said the Eyes of the Dragon seek those who briefly possessed something that was ultimately beyond their ability to keep...- Faithful Heart
Grafts to the user's chest, becoming one with the heart. Deems worthy those who believe they know a unique truth.
It is said Faithful Hearts seek those who believe they possess a special knowledge that is theirs alone...- Hand of the Dead
Replaces one of the user's hands. Promises a second chance to those with nothing left.
It is said Hands of the Dead seek those who have lost everything and yet still have the will to struggle on...- Orb of Power
Grafts to the user's chest, absorbing and replacing the heart. Found by those who seek the forbidden.
It is said Orbs of Power seek those who search for what should not be found...- Titan's Fist
Replaces one of the user's hands. Drawn to those whose strength was not enough.
It is said Titans' Fists seek those who lacked the strength to achieve their dream...- Vodun Mask
Adheres to the user's face, obscuring it forever. Found by the very fortunate and very misfortunate alike.
It is said Vodun Masks seek those whose fortune, whether good or bad, is great in magnitude...
It becomes very clear that there is a theme of loss and the power to take back or otherwise fight against the loss or isolation, which could mean that the Relics are either trying to help in their own strange way, or going after the easy marks.
wizzzargh wrote:Antoria is a mighty wizard of Tower:20 who rejected a Relic so I think it's pretty safe to say all the relics are horrible parasitic things with agendas of their own that nobody but the ignorant or the desperate would willingly bond with.
Further enforces this idea that the Relics are far from benign.
Wraiths wrote:
- Orb Wraith
The Orb, having no use for the host's material form once it has expired, has discarded it while converting the soul into various elemental energies.- Fist Wraith
Energy released in a sudden surge from the Fist not only reanimated the summoner's corpse, but granted it even greater size and strength than the Fist bestowed in life. But why did it wait until after death to give such might?
With the way they seem to be empowered further by the death of the Summoner, the idea of the Relics being anywhere near benevolent gets less and less traction. But what good is a dead Summoner/Wraith, and why do they only show any sign of life when disturbed by a living Summoner?
Last updated on 2/23/2017
But, I should caution that it isn't Demon's intent to place large amount of emphasis on story elements. That said, I do have some consistent themes/threads I'm trying to stick with. 
