I'm playing as a maxed out Promethean/Mathemagic wizard, currently on Floor Nine. Typical play is casting tactical pyre and recursive/Beklan's curse. I'm currently holding the normal mirror shield in the other hand, and with the coat of denim have a magic reflection stat of 54 , but that option of 100+ is looking pretty good... Any help is really appreciated, thanks TL;DR: Is getting 100 by picking up Dark Mirror Shield worth the resistance penalties (-3 , -3 ) and losing the benefits to magic from Orb of Nothing?
Keep both for situational advantages if you can be bothered to frequently switch items. If you already have 54 reflection , though , the only thing you'll really need that mirror for is fighting Dredmor. 100% reflection may also be useful if you meet 5 Djinn Fizz at once in a level 10 zoo. Note that the darkly shield will cast eldritch curses on enemies you hit , which feature a nasty area of effect. Try not to use it when you are cornered by monsters without your drake.
Does reflection add or is it calculated separately? e.g. do two 50% reflection sources give you 100% effective reflection or 75% effective reflection (50%, then 50% of the remainder)?
So If I grab two mirror shields and have the berserk skill that also grants reflect, and a handy enchant I am immune to all magic? Interesting.
Magical projectiles, yes. I believe there are still spells that can affect you directly, magic resistance being used against them instead.
So would thor's fulmaric bolt count as one that could be reflected? If not time to grab all the ulmesh stuff I can.
Only spells that fire a "projectile" can be reflected. Dredmor's fireballs and the aethereal missile spell from octos are examples of projectiles.
Thor's F. Bolt is one spell that is specifically not protected against by magical reflection. You can still be hit by that (came as a nasty, could have been fatal, surprise to one of my characters with . So dazing or anti-magicking are still good ideas against many a dangerous dude.
Thor F bolts and Arctic Wind are not deflected by . This is of course the 2 worst spells Dreadmor can throw at you. However if you get some decent and a time lord scarf then you should be able to defeat Dreadmor without cheesing anti-magic.