Artifacts
note that stat and resistance bonuses are cumulative, but skill bonuses are not, even with a set. So wearing death boots and death cap will give you only +2 dark!
A number of effects, like 'of the Jitterbug', are undocumented (don't exist as normal item attributes) and unknown to me.
notes on the columns:
set: whether the artifact is part of a (class-specific) set, that gives extra bonuses when complete. Each of the 4 sets has 5 parts.
restriction: extra restrictions, above the normal ones, like mages may not use plate armor.
listed effects: The effects listed in the description. When a target is not specified, it's the most logical one; like for stun it's the target, unless specifically mentioned.
notes: mentions if there is a fixed location the artifact can be found, and mentions if the description of the artifact differs from the effects seen in the Stats and the Skills screens.
name	type	sub-type	set	restriction	price	listed effects	notes
Broderick's Amulet	amulet	-	Broderick	crus., pala.	13000	+2 blade; +2 armsmaster; with complete set: of Armsmastery	OK
Fre's Heart	amulet	-	- (!)	-	25000	+50 HP; -10 SP; of Regeneration; Fragile	OK; no breaking noticed yet
Mountbatten	amulet	-	-	-	20000	+5 dark; +3 perception; of Amelioration; of Lurking	OK
Pendant of the Spheres	amulet	-	-	-	23000	+5 to all magic skills; +3 learning; +3 meditation	OK
Screever	amulet	-	-	-	20000	immune to all conditions; -3 learning; gain only 85% of normal experience	WARNING: this artifact drains Xp in stead of rewarding less; equip at your own risk!
the Green Man	amulet	-	-	-	30000	+20 SP; +3 Meditation; +5 Light; +5 Spirit; of regeneration	OK, fixed location: gift from the Green Man (Frosgard)
Broderick's Hauberk	armor	chain	Broderick	crus., pala.	13000	AC 32; +2 blade; +2 armor; with complete set: +10 to all resistances	OK
Poltergeist	armor	chain	-	-	25000	AC 20; of regeneration; 10% chance opponent becomes afraid	OK
Death Cuirass	armor	leather	death	scholar, lich	15000	AC 40; +2 dark; +2 meditation; with complete set: +10 to all resistances	OK
Igdrasine	armor	leather	-	-	25000	AC 18; +10 Magic	OK
Prize Plate	armor	plate	prize	merc., glad.	10000	AC 60; +2 body building; +4 Might; with complete set: +10 to all stats	OK
Swordsbane	armor	plate	-	-	20000	AC 75; +40 AC versus melee attacks; -10 AC versus ranged attacks	OK
Hubris	belt	-	-	-	20000	AC 6; +30 Might; increased to hit; of Endurance; of Protection; of Arms Mastery	difference: AC 20 in total
Death Boots	boots	-	death	scholar, lich	15000	AC 7; +2 dark; +2 ID monster; with complete set: +20 Speed	OK
Fre's Chain Boots	boots	-	Fre	healer,priest	15000	AC 7; +2 light; +2 Speed; with complete set: +20 Speed	OK; location: possible gift from the genie, Ruined Temple, Frosgard
Walking Boots	boots	-	-	-	20000	AC 20; +10 Speed; +10 all resistances; of Everlasting, of Regeneration; of Amelioration	OK
Broderick's Gloves	gloves	-	Broderick	crus., pala.	13000	AC 10; +2 Blade, +2 Vita; with complete set: +10 to all stats	difference: no +2 vita (?); +2 light
Fre's Gloves	gloves	-	Fre	healer,priest	15000	AC 7; +2 light; +2 repair; with complete set: of Item Repair 3	OK; location: possible gift from the genie, Ruined Temple, Frosgard
Laet'ax	gloves	-	-	-	25000	AC 30; -10 Accuracy; +10 Luck; +5 disarm traps	OK
Broderick's Helm	helmet	-	Broderick	crus., pala.	13000	AC 12; +2 blade; +2 might; with complete set: of Regeneration	OK
Brongnoker	helmet	-	-	-	35000	AC 25; +10 to all Stats; +10 armor skill
Death Cap	helmet	-	death	scholar, lich	15000	AC 8; +2 dark; +2 learning; with complete set: of the Jabarb	OK
Fre's Helm	helmet	-	Fre	healer,priest	15000	AC 13; +2 light; +2 meditation; with complete set: +10 to all resistances	OK; location: possible gift from the genie, Ruined Temple, Frosgard
Prize Skullcap	helmet	-	prize	merc., glad.	10000	AC 3; +2 body building; +2 armor; with complete set: of Regeneration	OK
Witchbane	helmet	-	-	-	25000	AC 15; +20 to all resistances, +20 AC against magical attacks	OK
Death's Ring	ring	-	death	scholar, lich	15000	+2 dark; +2 elemental; with complete set: +10 to all stats	OK
Fre's Ring	ring	-	Fre	healer,priest	15000	+2 light, +2 spirit; with complete set: +10 to all stats	OK; location: possible gift from the genie, Ruined Temple, Frosgard
Lubricious	ring	-	-	-	20000	+20 AC; +5 dodging; -3% damage	difference: no damage penalty visible in Stats screen
Prize Ring	ring	-	prize	merc., glad.	10000	+2 body building; +2 learning; with complete set: +10 to all resistances	OK
Soulband	ring	-	-	-	15000	+5 light; +3 meditation; +50 SP; of Speed	OK
Sturkabygel	ring	-	-	-	20000	+10 Might; +5 Endurance; +100 HP	OK
Weregild	ring	-	-	-	20000	+1000 gold per week; -40 party Endurance	difference: no Endurance penalty detected
Arrowfoe	shield	-	-	-	20000	AC 60; +30 versus missiles	OK
Prize Shield	shield	-	prize	merc., glad.	10000	AC 0; +2 body building; +2 dodge; with complete set: spry *	OK
Sygnir	weapon	blade, axe	-	-	15000	damage 28-43; Fragile; extra damage; +6 armsmastery; +6 blade; Regeneration	OK
Bloodaxe	weapon	blade, axe 2H	-	-	20000	damage 38-53; 40% poison (at GM); +20 Endurance; +10 to all resistances	difference: no Endurance bonus
Black's Heart	weapon	blade, dagger	-	-	23000	damage 25-50; increased damage; increased to hit; increased Speed	OK; fixed location: Kluso's house, Drangheim
Integris	weapon	blade, dagger	-	-	20000	damage 37-47; +35 to hit and damage; +15 pts. poison; Fragile	difference: no hit and damage bonuses visible
Excala Banna	weapon	blade, sword	-	-	20000	damage 29-49; -5 Accuracy; -5 Endurance; +50 Luck	difference: +15 Endurance
Jorgamesh	weapon	blade, sword	-	25 accuracy	21000	damage 28-43; -50 SP; +20 accuracy; +10 Speed;	OK
Mevan Sword	weapon	blade, sword	-	-	1500	damage 45-85; breaks after first use	OK
Prize Gladius	weapon	blade, sword	prize	merc., glad.	10000	damage 20-30; +2 body building; +4 armsmaster; with complete set: +40 to hit	OK
Sing Sword	weapon	blade, sword	-	-	20000	damage 27-37; +30 Might; of Armsmastery	OK
Broderick's Twohanded Sword	weapon	blade, sword 2H	Broderick	crus., pala.	13000	damage 30-35; +2 blade; +2 learning; with complete set: +40 to hit
Everstrike	weapon	bow	-	ranger,priest	25000	damage 40-50; 100% accurate	fixed location: below Dook's castle, Guberland
Kraftig Bage	weapon	bow, crossbow	-	-	25000	damage 30-45; +10 to all stats; +7 bow	OK
Blackpowder	weapon	bow, musket	-	-	30000	damage 50-60; bypass AC; extra damage; slow reload;  20% breaking and damaging user	No breaking noticed yet
Spencer's Obedience	weapon	cudgel, club	-	-	20000	damage 33-57; +10 Speed; very fast; of the Jitterbug	OK
Blutterbunger	weapon	cudgel, flail	-	-	15000	damage 26-56; 5% stun; of Bruisers; of Edge; when fail vs. skill: 70% knock self unconcious	difference: +5 Cudgel (might be 'of Edge')
Manarus	weapon	cudgel, flail	-	-	20000	damage 30-55; +80 SP; of Grandmasters; of the Jabarb	OK
Death Hammer	weapon	cudgel, hammer	death	scholar, lich	15000	damage 29-41; +2 dark; +2 armsmaster; with complete set: of Death	OK
Mjulnir	weapon	cudgel, hammer	-	-	35000	damage 33-48; +16-25 elemental damage; +60 Might; divine intervention always fails; -20 Speed	difference: no Might bonus; clarification: divine intervention only fizzles when cast by wielder
Vanir's Hammer	weapon	cudgel, hammer	-	-	20000	damage 37-45; +30 Might; +10 Endurance; 5% chance of enraging target (at GM level)	OK
Fre's Smooth Mace	weapon	cudgel, mace	Fre	healer,priest	15000	damage 28-36; +2 light; +2 might; with complete set: of Body	OK; location: possible gift from the genie, Ruined Temple, Frosgard
Samarjit	weapon	cudgel, staff 2H	-	25 might,   30 accuracy	20000	damage 36-54; +20 Endurance; +20 Might; of Everlasting, of Diamonds, of Masters	difference: Might +80; Speed -20
Formanir	weapon	spear	-	-	35000	damage 47-63; -10 AC; -20 Endurance; +30 Might; of Grandmasters; of Everlasting	difference: 'only' -10 Endurance
Gungnir	weapon	spear	-	-	35000	damage 38-62; of Puncturing (20% chance of bypassing AC); extra damage	OK; fixed location: Inventa Storca, Thronheim
Einherjar	weapon	spear, halberd	-	-	20000	damage 40-65; Vampiric; +20 Might; 10% /week of user going insane; 10% /week of user -30 HP	OK (no insanity or HP loss noticed yet)
Stouka Couta	weapon	spear, halberd	-	-	20000	damage 29-65; 5% chance Enrage (GM); +30 Might; +10 Endurance	OK
Tillhygge	weapon	thrown, axe	-	-	20000	damage 40-50; +30 Accuracy; +10 Strength; of Disease; of Mastery	OK (note: of Mastery = +5 Item repair)
Trolleri	weapon	thrown, dagger	-	-	15000	damage 37-51; slow; +100 HP; 3 attacks	OK