according to manual : for soulslay
penetration is 11 + (lvls in astral - 3 ) :2 ( rounded down ) + 2d6
are the 2d6 open ended or not ? the manual doesn't write open ended .
now the magic resistence of the target is :
MR + half the skill in the spell ( here astral / 2 ) + 2d6
you can get additional penetration through :
+2 runesmasher
+2 spell focus
+1 ring of sorcery / wizardy
(+2 from the unique the green eye )
so in general +5 maximum
are the boni cumultative ? +4 for 2 spell foci or only +2 ?
while there are many mr-increasing items
around +10 should be very possible
a pretender has a base mr of 18 . if he doesn't have any astral skill and no mrincreasing equipment but the astrologer doesn't have too :
mr of the pretender of 18+2d6
the astrologer would have 11+2d6 penetration
if both values are equal is it considered a hit or not ?
if yes the astrologer could only hit if he has a 7 higher dice throw
if no only with a 8 higher dice throw
if the pretender uses very good mr equipment :
amulet of antimagic +4 , rainbow armor +3 , starshine skullcap +2 ,lead shield + 4 = 13
without open ended 2d6 throws the astrologer would never hit , with +6 penetration +7 in astral magic the values would be :
19 +2d6 for the astrologer
18+13 for the pretender so the astrologer would never hit right ?
but even with open ended dice rolls i think it is stochastically very rare he hits the pretender , 1 time out of at least 10000 or so .
the pretender should not go astral magic because of magic duel normally .
so conclusion : your normal advantage is 7 or 8 depends on the rules .
lets assume 7 . then you normally only need to get + 10 mr to be only hit successful via soul slay even if the attacker has astral lvl 5 + penetration bonus of 4 via a lucky open ended dice roll .
much more he will not have expect in the very late game .
is this quite true or did i forget something ?
