Spell:Blood Bank

Birthright spell

The caster can transfer the bloodline of a willing scion into a gemstone of the appropriate type. Source: BoP

This spell stores almost the entirety of the scion's bloodline in a gem, and is typically used before some dangerous quest to preserve the bloodline in the event that the scion is slain. The spell is usually cast only on a willing participant, but can be cast on someone unwilling, in which case they get a will save at +1 for every 10 points of bloodline strength vs DDC equal to 10+ the caster's spellcaster level to avoid the spell.
If the scion dies, then the bloodline 'banked' is unaffected by the death, and only the residual bloodline (which canot be reduced below 1 point with the spell) is released in a regency storm. The bloodbanked bloodline can be invested in someone just as any other bloodline can be transferred.
If a bloodbank gem is destroyed, or the spell ends, while it holds a bloodline, then the effect is as follows:

• Bloodbank is in contact with its scion: Bloodline & regency return to the scion in full.
  

• Bloodbank is within 10' of its scion: Half the bloodline & RP return to the scion, the residue creates a regency storm as if a scion of the half bloodline strength had been slain (if the destruction was deliberate) or passes to the scion's heir (if not - DM's call).
  

• Bloodbank is further away from its scion: The bloodline is released in a regency storm / passes to heir at the DM's whim.
  

The gemstone used for the bloodbank must be of the correct type, and be worth a significant amount. To work out the necessary value, convert the entire bloodline of the scion barring the last point into regency points, then require a gem worth 10 GP per regency point. (This is purely a mathematical issue, the bloodline does not, in fact, convert to regency).
A simple formula for the gemstone value for a scion of bloodline 'a' and regency 'b' is: [([a*(a+1)]*0.5)-1+b]*10 = cost. if the gemstone is of insufficient value (likely for scions with a powerful bloodline) then only some of the bloodline can be banked.

BLS	Cost
10	540
20	2,090
30	4,640
40	8,190
50	12,740
60	18,290

Note that the gemstone stores the 'top' bloodline strength first - so a scion with a bloodline of 60 would need a gem worth 5,550 gp just to store 10 bloodline points.
The types of gem required are:

Bloodline	Gemstone
Anduiras	Red Ruby
Azrai	Black sapphire
Basaia	Bright yellow topaz
Brenna	Deep orange jacinths
Masela	Blue sapphires
Reynir	Emeralds
Vorynn	Diamonds

If the gemstone is worn by the scion next to their skin, then the scion is treated as though they still possess the bloodline directly. If it is not in such proximity, then the scion has an effective bloodline of 1, and can barely collect or spend RP making rulership very difficult.

The scion should make sure that they are in flesh contact with the bloodbank on expiry of the spell, or the bloodline could pass to their heir as if they had been slain - or pass to another via the Land's Choice. It is said that sometimes, particularly if the scion has a very different alignment to whichever of the old gods whose bloodline that they hold, some of the bloodline might remain in the bloodbank transforming it into a sielshegh.

The spell is typically cast as a protective measure when the regent fears they may be the victim of bloodtheft in the near future - for example when personally undertaking a dangerous diplomatic mission to another scion's court.
Many scions dislike the concept of this spell, their bloodline is part of their very nature, to surrender it in any way is almost unthinkable to them.
A powerful dispel magic cast on the scion might sunder the link between them and their bloodline (DM's whim) this would have little practical effect beyond requiring an investiture action to recover the bloodline.
It should be noted that the use of this spell before visiting another regent could be taken as a severe insult - even the Gorgon pretends to the traditions of ancient Anuire it is said, and the bloodbank clearly states that the scion expects the usual protections between host and guest to be ignored by the host.

In AD&D this is a prayer of the Guardian sphere. As AD&D did not have a regency storm (likely due to legal issues in relation to Highlander), the destruction of the Bloodbank will follow the usual 2e rules for slaying a scion.