This is a guide for blue mage tanking in Sheol C while utilizing Cruel Joke.
The Party Setup:-
BLU/RDM, DDx2, COR, BRD, WHM.
BRD: Mambo x2, Ballad x1, honor march x1, or Minne x2 .
BLU Tools:-
Buff: Aquaveil, Cocoon, Phalanx ,Occultation, Erratic Flutter , AM2 (After sleeping mobs tp on one monster till you can get AM2 before casting Cruel Joke on mobs)
Heals: Restoral(self heal), White Wind(party Heal)
Enmity+: Actinic Burst (Flashga), Temporal Shift (Stunga), Fantod
Debuffs: Reaving Wind (TP removal), Tenbral Crush(DEF -),
Silent Storm (Silencga), Rending deluge(Dispelga)
Recommended Food: Miso Ramen +1
Battle scenario:-
Nostos Group:-
Buff >> Pull first Group >> Dream Flower or Sheep song (BRD may assist)>> Pull Second Group to the First Group >> Dream Flower or Sheep song >> Cast Cruel Joke on both groups >> Cor Uses Random Deal/Wild Card >> Repeat the process.
Note: The party can kill other nostos group while Blu is handling/looking for groups that vulnerable to Cruel Joke.
Halo Group:-
Buffs > Pull all >> Sleepga(BRD may assist) >> DDs Destroy Halo >> Cruel Joke on regular mobs >> DDs kill Halo Mobs with blue mage support.
Groups that resist Cruel Joke:
Full Buff > Pull a group >> Cast Dream Flower >> Actinic Burst >> DD Kill.
Note: Cruel Joke's Effect wears off if walking more than 10' from the target.
Gear Sets:-
Cruel Joke Set:

http://www.ffxiah.com/item-sets/381679
Cape: 20 Int 30 Macc/mdmg 10 PDT
Note Use this set for Dream Flower on 3rd and 4th floor.
Other option for Ear: Crepuscular Earring from Shinryu, Use Acuity Belt outside of Odyssey.
Weather Affect Macc: Wiki Page for more information
Tanking evasion Set:

http://www.ffxiah.com/item-sets/381678
Rosmerta's Cape
Agi 20 Eva 30 20 MEVA
Fast Cast 10
Recommended: Sakpata's Sword Augmented.
Enmity Set:

http://www.ffxiah.com/item-sets/381680
Note: Use it for Temporal Shift, Actinic Burst and Fantod.
Note: you can use similar equipment as the above for rings earring waist, back.
Phalanx set:

http://www.ffxiah.com/item-sets/381677
Phalanx 3+ Fast Cast +5
Note: use this before pulls only.
Fast Cast Set:

http://www.ffxiah.com/item-sets/381684
Rosmerta's Cape
"Agi 20 Eva 25
Fast Cast 10
20 EVA MEVA"
Note: Use this set for Tenbral Crush, White Wind , Silent Storm and Cocoon.
Blue Magic Skill:

http://www.ffxiah.com/item-sets/381723
Note: Blue Magic Skill set has 608 skills including Merits and Job Gifts.
Rosmerta's Cape: same as the above.
Other option for Ammo: Mavi Tathlum
Other option for Waist: Witful Belt
Other option for Back: Cornflower Cape (Augmented Blue Magic skill 5-15)
Note: Skills 599~649 = 12 shadows, 650+ for 13 shadows.
Note: Use it for "Occultation", only before pulling a group.
Note: All UNM equipment's are augmented.
Blue magic Spell List:
Fantod
Tenebral Crush
Reaving Wind
Cocoon
Screwdriver
Silent Storm
Tempestuous Upheaval
Dream Flower
Sheep Song
Rending deluge
White wind
restoral
Delta thrust
Barbed crescent
Erratic Flutter
Occultation
Temporal Shift
Actinic Burst
Sudden Lunge
List of Sheol C Mobs vulnerable to Cruel Joke and Sleep spells:-
Proof of concept:
#1 Odyssey C annihilations segment earned 13610
https://www.youtube.com/watch?v=98c_...83%88%E3%83%AB
#2 Odyssey C annihilations segment earned 14117
https://www.youtube.com/watch?v=l3-o...83%88%E3%83%AB
Credit to HeadSparkle
I hope this guide encourages blue mages to tank in Sheol C, Thank you.
Credits for Gearsets and spell set: Headsparkle.