Tolkien's Dragon-Spell

The Glance of Glaurung by Alexey Rudikov

In Middle Earth, dragons have an ability known as the dragon-spell. This is essentially described as a kind of hypnotic voice/gaze, allowing them to manipulate humans and elves to their will. Dragon-spell could create feelings of distrust, influence the target's perception of the truth (as with Smaug), and even lead to total memory loss and madness (as with Glaurung).

This ability has been connected to dragon-sickness, in which individuals exposed to a dragon's hoard (especially after the dragon's death) can be overcome with greed.

Further information on these can be found at A Tolkienist Perspective and the Lord of the Rings Fandom Wiki.

I wanted to have a go at making these traits into mechanics that could be used for dragons in tabletop games, using D&D 5e mechanics for this entry with the knowledge that they could then be converted into other systems as and when needed.

Sacrifice to the Green Dragon by John Tedrick

Dragon-Spell

Dragons with this capability gain the following additional traits:

Roving Eyes. The dragon targets one creature within 120 feet that can see the dragon's eyes. The target must make a Wisdom saving throw or be charmed by the dragon. At the end of each hour, the target can repeat the saving throw, ending the effect on a success. On a successful save, the target is immune to this dragon's Roving Eyes for 24 hours.

Serpent's Tongue. if the creature can understand the dragon, it must make a Charisma saving throw or become influenced by the dragon indefinitely. A creature that cannot understand the dragon is unaffected by this ability. Before the saving throw is made, the dragon chooses one of the following effects to apply to the creature if it fails the saving throw:

False Truths. The dragon manipulates the target's perception of the truth, creating feelings of greed, loyalty, distrust, or any other desired mindset.
Memory Loss. The dragon clouds the target's memories, causing partial or total memory loss. The dragon can only remove memories in broad strokes (e.g. "your childhood" or "your time in the castle").

The effect can be ended early by the dragon speaking a command word as a bonus action, or by a remove curse, greater restoration, wish spell or similar ability.

Dragon Sickness

This counts as a curse that starts when a dragon dies. Within 1d4 hours, the hoard becomes infested with the curse. Any creature that comes within 30 feet of the hoard must make a Wisdom saving throw. On a failed save, the creature is afflicted with dragon sickness. On a successful save, the creature is immune to this hoard's dragon sickness for 24 hours. A creature with dragon sickness gains indefinite madness (DMG, pg 258-260), adding the following flaw to their character: 

"protecting the hoard is all that matters to me now."

The character puts the hoard above all else, and the hoard intends to keep things that way. At the DM's discretion, a particularly large hoard may also provide the following effects to a cursed individual:
- They only eat and drink half as much as a regular person, and sleep half as long
- They are immune to disease
- They have advantage on saving throws against being charmed or frightened
- They age at 1/3 of the rate of their normal race

Dragon Sickness can be cured as with any other indefinite madness. At the DM's discretion, a character may also be able to repeat the saving throw after an extended period of time away from the hoard, or if their desire to protect the hoard conflicts drastically with their character bond (such as with the case of Thorin choosing between the hoard and aiding his allies in battle). Should additional effects be used, the target returns to their own mind with 1d4 levels of exhaustion (no more than 4 total) and their age catches up to them.

Dragon's Hoard by Adam Paquette

I would potentially consider also adding this effect to magic items within the hoard as a curse, similar to the effect on items stolen from the lairs of Mummy Lords (MM, pg 229). Straight up taking the specific regional effect would also work fine.

I also feel that these abilities would work well together with the 'words of power' used by dragons in Skyrim; perhaps instead of traditional breath weapons, they use effects similar to power word stun, power word pain, or power word kill?