There are some great suggestions and I am late to this post so I am sure I am late, and Admittedly I am incorporating some of the Ideas built in this room as well as on my own/Inspiration taken from MTG and Warhammer, So here is my take on a CE God of Joy,Mirth and Death.
A Religious Nomadic culture ruled by Priestly Entertainers. The Jesters who call themselves priest of their God insert bring joy and mirth to all their willing victims.
There Temples have all a soul could desire, The finest wines and foods. More earthly pleasures of Man and Woman, who offer themselves to those who come, They give all they can and ask never for anything in return. Sex, Drugs, Rock and roll. Everything is acceptable and everything has a Price. As the Travelers, and citizens indulge, There stand the Masked Priest watching looking and judging.
The Temple filled with scents of lilac and burning seeds in the brazier seem to have a affect which compel and seduce you to all the pleasures.
But they do not just preform and show each offering a test each word a gracious gift. Give freely, Smile and rejoice, celebrate death and love all. On the surface this seems positive. One who is uneducated might even think that there is comfort in not morning the dead for their suffering is over. Always they are watching from behind their mask...waiting for someone to have just a little too much fun. That's when the Slaughter games begin.
A Ritual performed on each new moon, those deemed unworthy are offered to their god for judgement. Those who God name here wants at his table are given the swiftest path to their Smiling god of death.
You will smile and be joyful.
You will sing with your neighbors, even the ones you secretly hate because they always take a little more than they give.
You will forgive because happy people don't hold grudges.
And so I say this to you, smile and find peace.
Life is full of pain and suffering and the only way to escape is through death and you better come to me with smile on your face or you shall no endless pain.
But if You greet me with a Smile, Than you are my friend and we can play and sing all day. In death I see your true face, so wear a mask and hide your smile because I am the only one who will see it.
They kidnap those from their temple who took to much or over indulged, and wait for their judgement, they offer freely of their talents as they travel never staying anywhere long as to not draw too much attention or overstay a welcome.
They do their gods work and offer joy and happiness even if for a brief moment.
It should be noted I have built this culture as Nomadic but also they all wear masks protecting their 'true faces as to offer a true gift, as children they build these mask, as adults they are only removed at death to see if they had a good death aka a smile on their faces, To new comers who wish to join after a 'baptism' They are given a mask. I in my campaign where I uses these people I just was enthralled with Masks for these Jester
Bards - Jesters Masks often Resembling Scarecrows or Goblins, Shaven heads with wigs of Straw. Light-Med armor, Sickle & Whips, War casters & Dual Wielders
Fire Breathers - Jesters Masks often Resembling Scarecrows or Goblins, Shaven heads with wigs of Straw. Light-Med armor, With Torches granting them Breath weapon feature and Short swords or another Finesse weapon Or you could just do Sorcerer Dragon bloodline alt for firebreathers
Rouges: Knife Throwers Dressed in flamboyant cloaks with mask often resembling skulls or trolls.
Jugglers: Armed with academical flasks.
Clerics - Clown - Silver mask built as Skull, One handed Blade Medium armor Limited Plate - Medium Armor Master,Sentinel
Paladins - Harlequin - Black robes with flowing cloaks, Golden chain mail and Plate Winged swords with their holy symbol in the Hilt,Generally Two handed Solid black mask without seemingly eyes but a bright golden and silver smile
Sorcerers - Trickster light armor Flamboyant robes which appear worn and tattered, often with horned skull mask with silver/gold spikes. Wild Mages
Also I have used Succubi,Incubi Some lesser demons as alternate bad guys here. I do have a Arch Paladin who is Tagged with Lord of Riots tag.
That's my take on a God of Joy and Death, I do want to thank this post for inspiring and helping me build and work it into my campaign im sure it not perfect but everyone seems to love our crazy death carnival