I haven't played D&D in about ten years — previously I had DMed 3.5 and 4th Editions — so it was my first time playing as a PC at an after work 5e campaign. We played an one-shot then an adventure that lasted about twelve sessions (the DM originally said it was suppose to last about six sessions).
Our level 5 party (a dwarven cleric (war), a dwarven bard (college of lore), a tiefling wizard (evocation), a drow rogue (thief), a human ranger (hunter), a tiefling rogue (swashbuckler) (who latter switched to a loxodon cleric/warlock 75% into the adventure), and my protector aasimar paladin (oath of devotion)) were on a ship but it suddenly got frozen just off the coast of an uncharted island — think Lost.
We found a temple near the beach where there were twin intelligent talking baboons who have been stuck in there for a couple hundred years — being stuck inside the temple for so long they loathed each other's presence! They told us the only way to get off the island is to deactivate six shrines located around the island. Some deterrences we discovered on the weird magical island was that the weather changed every day (from raining blood to a blizzard to darkness throughout the day) and a daily omen that the cleric casted Augry to see what ill could strike us if we do/don't do something like backing our steps or travel during the day).
We stumbled upon a cave where a lonely white dragon had a stage set up by his kobold minions — they mistook us for new performers. The bard was shoved on stage by the kobold stagehands and he rolled two Natural 20s for his Performance check with his bagpipes and made the dragon cry, moved by the performance. Unfortunately the tiefling swashbuckler player had to leave the session early to pick up his wife and told the DM he would attack the kobold stagehands before he left. That of course enraged the dragon — being an Oath of Devotion paladin I jumped in front of the bard and took the full blast of the frost breath weapon (twice in fact after the bard healed me after the first blast). The rogue jammed the mechanism that closed the hatch in the ceiling so the dragon couldn't fly out of the cave through the vertical tunnel so when it did try, it was stunned it and fell back down. In the end, we managed to kill the dragon no thanks to the swashbuckler (I got an adamantine plate armour and a kobold-sized white dragon outfit that I used as a shoulder cape in honour of Bahamut).
At another shrine we found a vampire who was willing to swap a chest full of treasure in exchange for blood which we (minus the missing swashbuckler player), being level 6 characters at the time, agreed to since we couldn't handle a CR 13 vampire. However, the next session the swashbuckler player didn't know we had signed a contract in blood and decided to attack the vampire. Not surprisingly we were getting our asses kicked so being a paladin with high Charisma score I did Persuasion roll of 26 to call a ceasefire and told the vampire the swashbuckler would offer two bites worth of blood in exchange. That satisfied the vampire and we walked out with the treasure and weakened (our max HP were lowered).
Other shrines had demons or hinted at influence by Demogorgon and when we deactivated the last shrine a beam of light appeared back at the temple where the twin baboons were. We trekked back to the temple and found in the foyer the twin baboons had gone crazy and wanted to attack each other now that they were finally free from the temple. We tried to stop them but a blast from the other room had knocked everyone on their backs. The twins merged into a giant two-headed monster and we slew them. We went further down the temple and discovered a maze with murals dedicated to Demogorgon. In one of the rooms was a statue of the demon lord which caused people to start worshiping him if they failed a Wisdom throw (being a 7th level paladin now I had an Aura of Protection, which offered a +4 to saving throws to everyone in a 10' radius) so standing at the entrance of the room helped my party to avoid failing their saving throws. We later found a murky fountain and luxodon cleric/warlock touched it and got telepathic linked to an aboleth, who was a servant of Demogorgon. The aboleth revealed that it was below temple and was going to summon its master into the Material Plane.
We went further down to fight the aboleth and its kuo-toa minions guarding sacrificial altar, a crown on a pedestal in front of a magic portal on the other side of the water-filled chamber. As a protector aasimar, my paladin released her Radiant Soul power and flew above the water while the party was sucked closer to the aboleth (it was using its lair control power). My paladin, immune to diseases and charm, fought the aboleth hand-to-hand while the rest of the party shot at it with crossbows, bows, and magic from a distance. The luxodon misty stepped onto the altar to grab the crown, however, he failed a saving throw against the aboleth's Enslave power and was commanded to take the crown to the portal. The tiefling wizard casted a Darkness spell in front of the portal to stall the luxodon and giving my paladin enough time to grapple him and wrestle the crown from him after killing the aboleth with a massive amount of radiant damage from her divine smite. Just as my paladin got the crown the twin heads of Demogorgon started to pierce through the portal. The luxodon got hit by Demogorgon's tentacle, reducing his maximum by over 45 (I think he was down to like 4 HP at that point), for failing to bring the crown to the demon lord.
My paladin flew to the dwarven cleric to give him the crown (being an aasimar paladin she was very wary of wearing the crown associated with Demogorgon) and he wore the cursed crown (he got a boost to his Strength but became paranoid at anyone wanting to take a look at the crown) to close the portal. So even though we had just leveled up to level 7 the previous session we all dinged to level 8 because we defeated a CR 26 demon lord!
After the session I Googled to see if an ally who is under a Charm spell will still be affected when within a paladin's Aura of Devotion. According to Jeremy Crawford, the lead rules designer of D&D, said that the Charm effect will be temporarily suspended while in the aura.
Aura of Devotion: RAW is unclear. RAI is that being charmed is precluded/suspended while you're in the aura. #DnD