Rules for Fiend Summoning Ritual in 5e

[JamesIntrocaso]

In the continuing quest of finding ways for high level PCs to spend gold in 5e, I developed a fiend summoning ritual that has costly material components (some or all which might require a quest to find... DM's choice). The ritual has risk and cost associated with it. Take a look and let me know what you think.

I'd love to make more rituals like this for my game in the future so feedback is very appreciated!

http://worldbuilderblog.me/2015/09/24/summoning-big-fiends/

[weaseldust]

As always, this is full of good ideas. I especially like the requirement for celestial blood.

I'm not keen on the requirement that the fiend be hostile if it is summoned improperly. I like the idea that, as an intelligent agent, it could choose to either attack or attempt to make a bargain, depending on its personality and interests.

Out of curiosity, how do you think summoning a celestial would go? I can see something of the 'avenging angel' variety requiring fiend blood and sacrifices, but not, say, a unicorn. I'm thinking something like a pure-hearted person holding a barefoot vigil in the desert for 24 hours with no food or water. Or perhaps making a special vow, like chastity to summon unicorns and honesty to summon couatls.