As a fiend you have a +2 bonus to constitution

Fiends have a keen sense of smell, and are able to recognize the scent of blood from a distance

You have proficiency in the perception skill 

Fiends primary feed on the blood and fear of humans, however they can also survive by drinking the blood of other creatures, by consuming blood and fear they can quickly heal their injuries and become more powerful. For that reason, while fiends can also consume other kinds of foods, such as vegetables and fruits, most of them refuse to just live off by consuming regular food, since it will not heal their wounds or give them more power. Fiends require 1 ration of blood per week to sustain themselves, excluding any actions which require the usage of their blood. Every hour without blood past the seven days forces the fiend to suffer from a level of exhaustion. 

All fiends can consume blood of other creatures to heal their injuries, it is also implied that fiends can grow more powerful by consuming blood. While all fiends can consume blood to quickly regenerate, powerful fiends have shown to possess better regeneration.The flesh or blood of a fiend can be fed to other creatures, making them stronger and even giving them the ability of the fiend they’ve eaten, however this only works if the flesh/blood they ate came from a fiend that is still alive. To heal themselves by drinking blood your constitution modifier must be added to a 1d8 roll. This can be taken as a bonus action, however there must have been a creature with at least first stage bleeding within five feet of the fiend for this bonus action to be taken. 

Fiends can freely manipulate the blood in their body to form weapons.