Blood Dragon spells:

Bloodlust(Upgrade to Blood Magic and growth ability):  The amount of life force needed to use Blood MAgic (and thus power the form) is reduced.  The ability can be leveled four times, the effect increasing each time.

Six Feet Under(Upgrade to Grave Robber/One Foot In):  The amount of health stolen from both living and dead enemies is increased, and the amount increases further if living enemies are killed by the spell.

Continuing Sacrifice(Upgrade to Sacrifice/Grim Sacrifice):  The spell changes into a passive and always activated ability while in the form, and while the amount taken is reduced, it is constantly sapping at allies instead of being activated only once.

Fatal Hemorrhage(Upgrade to Hemorrhage/Paralyzing Hemorrhage):  The Hemorrhage spell has a greater area of effect, does more damage over time, and has a larger chance of paralyzing enemies.

Undead Blood Slave(Upgrade to Blood Slave/Blood Spatter):  Several fallen enemies rise to fight for the caster for several minutes.  When they are defeated or the spell ends, they exploded, harming surrounding enemies and having a slight chance of poisoning them.

Blood Tendril(New spell exclusive to the form):  The caster creates tentacles made of his, enemies', and even allies' blood, which will attack enemies automatically for a short time before disappearing.

Weaknesses:

Elemental:  Fire, ice, and especially light; and an average weakness to other elements.

Extreme fatigue:  The first several uses will leave Spencer comatose for several hours due to the extreme amounts of energy the form consumes.  Once he gets better at it, he won't be left unconscious, but it will still be extremely tiring.

Need for life force:  Due to the massive amounts of blood/HP needed to maintain the form, it greatly increases the need Spencer has for life force, so that it is almost overwhelming; like a sort of vampirism.  The only thing keeping him from attacking his friends is the strength of his will, and even that can falter.