Divert Teleport (VH)

Blocking; Resisted by subject spell 
When cast on the turn someone or something teleports, or plane-shifts out, this spell allows the caster to dictate where or when the subject goes. 
The caster must know the spell he is diverting; he uses the lower of his skill with Divert Teleport and the subject spell. If the caster wants to divert a Teleport into a plane shift (for example), he must know both spells and uses the lowest of his three skills. 
The resistance is resolved by comparing the margins of success of both spells – if the mage who is teleporting makes his roll by 5, then the mage attempting to divert him must make his roll by 6 or more to succeed. 
The Divert Teleport takes normal range penalties between the caster of Divert Teleport and the caster of Teleport (etc.), and the standard skill penalty for the destination that the caster wishes to send the teleporter to. 
The cost to cast the spell is equal to the difference in cost between the teleporter’s intended destination and his new destination. If a mage attempts to teleport 40 miles (9 energy), and another mage forces him to another location only 10 yards away (3 energy), the diverting mage will have to pay 6 energy. The same cost would apply if the destinations were reversed. The minimum cost to cast is 3, in any case (high skill will reduce this normally), and the caster pays the full energy cost whether or not the 
spell succeeds.

Example: 
Suppose Severin knows Teleport at 16 and attempts to teleport 100 yards away to his waiting carriage (skill penalty -2, cost 4). Two yards away stands Elsdon, who knows Divert Teleport at 18 and Teleport at 20, and who would prefer that Severin end up just above a lake which happens to be a mile away (skill penalty -4, cost 7). 
First, Severin makes his attempt, spending 4 energy and rolling a 10. 
Since he needed a 14 or less, this is success by 4. 
Elsdon, using a base skill of 18 (the lowest of his appropriate spells), takes a -2 for being two yards away from Severin, and a further -4 for his intended diversion – his effective skill is 12. He must roll a 7 (succeeding by 5), to win the contest and divert Severin. Whether he does so or not, the calculated cost is 3 energy, so Elsdon must pay the minimum cost of 3.

Cost:  As described above; minimum cost 3. 
Prerequisites: Magery 3 and Trace Teleport.

Item 
Any. Usable only by mages.  
Energy cost to create: 700.