Behaviour:
Sassy, inappropriate, insensitive, cheerful, cheeky, foul mouthed... y'know what? Imagine Deadpool but without the fourth wall breaking and extra voices.

The Rituals:
Every 100 years, he will wake up naturally, and will wander for a short while before falling back to sleep and vanishing. He will wake up when something terrible is currently under way or has happened. For example, he was present at the end of every major war after 1000 BC.Despite this rule, he can be summoned and repressed at any point in time. Here is how:

-Awakening: Be out in the middle of the woods, Preferably in Scotland or Ireland. Make a campfire, put ten pebbles around it and throw four pounds of pig meat into the fire. wait until the meat has burned and give a valid reason for wanting to see him as you sit with your legs crossed in front of the fire, eyes closed with your hands on your knees. You must also keep your head down or when he wakes up he will not be happy. You will know you have been successful when either a green or blue aura surrounds the fire - at which point you must be clear of the fire and sitting, still.

-Alabaster: Return to the point where you lit your "Awakening" fire and throw four pounds of salt and sand over the fire place. Once the aura has diminished, you must whisper quietly to yourself "Ma 'se ur toil e." [Please] To call on his father. After that, speak "Tha mi duilich." [I'm sorry] three times to him. Offer up one possession you are fond of and place it on top of the pile of salt and sand. Lastly, don't forget your manners! "Tapadh leat." [Thank you]
(The Irish Gaelic equivalent of these phrases work just as well.)

Abilities/Weapons:
-Appears differently to everybody, however he is always seen as a large breed of dog or wolf.
-He can teleport short distances of 100m in any direction.
-When he speaks, his voice is heard in whatever language an individual speaks best, however his Scotch accent remains.
-He can fly, conjure fire and small thunderclaps.
-He can others hallucinate mildly, but only if he has reason to. They would have to have done something unjust and/or need to see truth.
-He can also change between anthro and feral forms.

Weaknesses/soft spots:
-Once he is bound to a promise, he cannot disobey.
-Unnatural light - It frightens him, so don't bring a flashlight to the summoning ritual.
-The Alabaster ritual - It sends him back to sleep.
-He is far weaker during the day. He is also weakened by pentagrams, hexagrams, any spells and crucifixes (normal AND upside down).
- Sweets. He absolutely loves them. Especially licorice. In fact it might be an idea to bring licorice to the awakening ritual.

Miscellaneous:
Voice/accent: Scottish, tenor
Species: Large male canine, varying breed/species
Alignment: Chaotic Neutral Demi-God

Other necessary information:
looks like: As a large male canine, he is seen differently by each person who sees him. Some see him as a large breed of dog, others see him as a large grey wolf. His thick fur looks weightless and moves as such when he does. He has an aura around him, sometimes teal, sometimes lime-green. In feral form he is 4 feet at his shoulders and 6 feet long. In anthro form he is 7.5 feet tall with a muscular build and digitigrade legs. In a good mood, his eyes glow blue; in a bad mood, his eyes glow red; when filled with rage, his eyes are black.
Theme: Gorillaz - Clint Eastwood - https://www.youtube.com/watch?v=R5MWCnKeH2s