Hey,
since there are many different ways on how to play and gear up the Mosaic Sin, I wanted to take the opportunity to give you my approach and my two cents to this matter.
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The Build
The Skills
The Stats
The Gear
The Tricks
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The Build:
The Mosaic Sin uses the runeword Mosaic to not lose charges of any charge-up skill when attacking an enemy. Meaning that you can stack all the different charge-up skills and release them in a powerful attack without having to recharge those charges. While not losing them on attacks, you might still lose them when you do not refresh your charges by either not attacking with a consumer or a build-up skill. Meaning that you are on the hook to attack at least once every 15 seconds so that you do not lose your precious charges and therefore cleaning time.
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The Skills:
There are different ways of building the Mosaic Sin. I prefer to do it the following way:
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Martial Arts:
Max out:
Phoenix Strike
Blades of Ice
Claws of Thunder
Tiger Strike
1 Point Wonders:
Dragon Flight
Cobra Strike
Fists of Fire
Dragon Claw
Dragon Talon
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Shadow Disciplines:
Reach 16 Points with +Skills:
Weapon Block
1 Point Wonders:
Mind Blast
Fade
Burst of Speed
Claw Mastery
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Traps:
-
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Reason for this arrangement:
PS, BoI, CoT, TS -> max out for max damage.
CS, DC, DT, DF -> DF has nice utility pre-Enigma, CS nice leech, DT is my prefered finisher and DC can be used instead of DT if your first kick kills everything on the screen and you do not want to be stuck in the kick animation of DT.
FoF: Fists of Fire converts 3% physical damage to fire damage for every skillpoint (including +Skills), meaning it will reduce your life and manaleech and will make it even 0 when surpassing 33 skill points. One can now skill up to 25 points for example and still have 25% physical damage, which should be enough for a nice leech. But damagewise you do not need it and thus I prefer to have a high life and manaleech instead.
MB: Mind Blast is wonderful when you lose your charges but you are surrounded by strong enemies. You can turn them or stun them to build up your stacks again.
WP: Weapon Block will grant 1% block chance until level 16 and will afterwards grant 1% every 2 skill points. Thus it might not be efficient going any further.
Fade, BoS, CM -> situation-dependent, either go for resistances and damage reduction or for speed, CM for AR.
You can be maxed out with your skills by hitting level 86 (not having Mind Blast or Dragon Flight on the weapon base). The rest of the points can be used as you like. E.g. Fade, BoS, Weapon Block, Shadow Warrior/Master, Blade Shield. I would not put more points into Dragon Talon since your animation will get longer due to more kicks. This will make you stuck in the animation for longer, basically watching a whole screen of dead bodies for that duration.
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The Stats:
Strength - to wear gear
Dexterity - to wear gear
Vitality - rest
Energy - good joke
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The Gear:
Gearwise there are again split opinions. Here are some high-end items, which should max out your damage and survivability:
Helmet: Griffons, Andyface, Shako
Armor: Enigma, Treachery
Weapons: Dualwield Mosaic Claws (bases will influence your attackspeed)
Amulet: Highlord, Mara, Rare or Crafted Amulet with +3 MA / +2 Assa, FCR, Resistances, Life, Strength, Dexterity
Boots: War Traveler, Gorerider, Rare Trires Boots, Aldur, Sandstorm, Waterwalk...many options here, elite version better for more damage.
Belt: Arach, Thundergod, Rare Belt with Resistances, Life and Stats
Gloves: +3 MA with nice add, +2 MA with nice adds
Ring 1: Raven
Ring 2: SoJ, BK, Rare Ring with nice stats
Inventory: Torch, Anni, Skillers and SC with Resistances, FHR, Life etc. w/e you prefer or have.
Perfect Mosaic Base: Phoenix Strike, Claws of Thunder and Blades of Ice boost your damage output. All can roll up to +3. I prefer them in the given order but PS is expensive so CoT and BoI is also nice to have. Also you might want to save some skill points by getting a base with Mind Blast and Dragon Flight. Will save you several Skill Points in total.
Which are important stats on items in my opinion: Strength, Dexterity so you can spend stat points on Vitality for +3 health/point. MF always nice to have. +Skills will boost your damage. Resistances and Life so that you don't get one hitted -> only way for you to die basically since you leech plenty of HP (care, not for skeletons and certain monsters).
Important sidefact: the damage of your claws is irrelevant most of the time. The damage comes either from the skills directly (skill level) or from your boots (kick damage for DT). If you use DC, your claw damage becomes relevant. But I use it only as a backup skill so therefore your boots will determine your physical damage output most of the time.
Another interesting fact: you do not need a mercenary to kill everything with this setup. Meaning you have the freedom to chose any merc you like. A1 with Vigor and FireRes, A2 with Infinity for maximum damage, A5 with nice sword runewords...all up to you.
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The Tricks:
How not to lose stacks in Chaos Sanctuary: after killing the last seal guardian, Diablo spawns. But he takes his time so you will lose your charges if you do not have a trick at hand. One is to TP out of CS and go to a WP area, where monsters will be very close to the WP. Some people use Frigid Highlands but in my opinion there is a more elegant way to do this (also this does not work all the time because you have to go through TP and then WP and then back again and try to run up to Diablo if you do not have Enigma yet. Thus many people will fail to make it work for them).
The more elegant way is to make use of Mind Blast. Before killing the last guardian, make sure to turn at least one of his slaves with Mind Blast. Afterwards go ahead and kill the Guardian. The Guardian dies and takes with him all his slaves except for the ones you turned before using Mind Blast. Diablo spawning is triggered nonetheless and after a few seconds you can refresh your charges by killing the once turned monsters and then continue to kill Diablo without losing your stacks. This works very well and it is continuously repeatable, meaning you do not have to have Enigma or some Telekinesis charges.
I might hate myself for it for multiple reasons but...how to push your damage with shit cheap items: As I said before your main damage comes from your charges and this damage depends on +Skills alone. The funny part is, that the level of your charge will be retrieved only once when building up the first charge...meaning that you can stack your +Skills on one set of gear, building up some charges and then swap to a second set of items to have higher survivability. I personally use gloves and amulets to do so. Rings are also a valid option. But keep in mind that this will take away inventory space. This is heavy min-maxing damage and it might not be even needed because this build is strong enough to clear anything on players 8 (I mean it, even ubers with slight tweaks to the build) but it is a nice trick anyways especially for people who can not afford expensive gear.
D2:R