You have mastered the science of revivification, granting you the following benefits.
Facilitated Revival
You can cast Raise Dead once without expending a spell slot and without Material components, provided you use Tinker's Tools or another type of Artisan's Tools with which you have proficiency as the Spellcasting Focus. Once you use this feature, you can't use it again until you finish a Long Rest.
Life Transfer
You can siphon the animating magic of your Reanimated Companion to bolster yourself. When you or your companion takes damage, you can take a Reaction to gain a number of Hit Points equal to your companion's current Hit Points. The companion then immediately drops to 0 Hit Points and dies (triggering its Death Burst trait).
Superior Modifications
Whenever you create a Reanimated Companion, the companion now gains three options for Strange Modifications.