Generic, Text: Blood Pact

Starting at 2nd level your understanding of Haemomancy allows you to consume a Haemomancer Hit Die as an action to gain 1d10 temporary hit points. This can only be done once before you take a long rest.
After 9th level, add your Constitution modifier to this value.
At 15th level, add your Proficiency bonus and your Constitution Modifier to this value.
At 17th level, you are now able to consume an extra Haemomancer Hit Die before your long rest.