This is something I'm interested in as well. but more specifically what Masteries should I be focusing on.

my 6* Sinesha runs on:

offensive + livesteal artifact set

She has 

+28.620  HP
+849 ATK
+829 DEF
+67 SPD
+49% CR
+24% CD
+29 Res
+57 ACC

With skill 1 she attacks with an aoe and heals more than other monsters.
Skill 2 heals her and 25% the lowest monster 
the third skill doesn't need any substats (except spd ^^)

She is full skilled.
She can wipe out a complete arena Team, while my other tanky 5* Champs were killed.

I also use her for 12. campaign/brutal/stage 6 to farm xp for other monsters.

In late game i want to use her as a healer (very tank and a lot of spd). 
or relentless set with same specs SPD > HP > DEF > RES > ACC > ATK

Curlycross said:

Thanks! What Masteries do you go for?

actually:

 row -> colum (info)

offensive:

1 -> 1  (+75 atk)

2 -> 2 (K-Dmg +10%)

3 -> 3 (+Spd / kill) <- Giant Spider ^^

support: 

1 -> 1 (+810 HP)

2 -> 1 (+5% heal others)

2 -> 3 (heal champ if first enemy got killed)

There're better masteries than this... 

And i still farming good artifacts (5* epic's) before i master the masteries