To acquire the Shemhazai Esper, you’ll need to continue the story until you reach the Great Crystal. As you venture into the depths, you’ll encounter Shemhazai and you must defeat her to be able to call upon her in battle.
|45||91,136||Fire||Sagittarius Gem, Hi-Ether, High Arcana|
Shemhazai is primarily a magick-weilding Esper, so you can dispense with Protect for this battle and instead focus on Shell, which is incredibly important for this battle. If you’re properly leveled and keep Shell and Bubble up on all your party members, you should do well in this fight. That said, Shemhazai’s elemental weaknesses are random, if you guess the correct element by chance she’ll randomly change her weakness to another element, and she’s fond of using Silencega, so you might as well bench your Black Mage and Red Battlemage in favor of a melee-focused party: Knight/Bushi, Shikari/Foebreaker and a White Mage are ideal.
Keep your White Mage at a distance to mitigate the damage Shemhazai will do with area-of-effect spells and to avoid getting your whole party hit with Silencega, and prepare the Gambit “Self: status = Silence –> Echo Herbs”… or just weak a Rose Corsage. Even with Shell on everybody, some of Shemhazai’s attacks (Flare, Scourge and Shock, in particular) can hit for devastating damage, so try to keep everybody above 2,000~ HP. Depending on what the max HP are for your weakest character, you should tool a Curaja Gambit to automate exactly that.
Shemhazai has over 90,000 HP, which is only half as much as, say, Tyrant, but like most bosses, expect Shemhazai to benefit from a variety of stat-boosting augments when her HP are low, including Chain Magick, allowing her to cast spells instantaneously. Don’t get cocky when you see her HP bar drop go below 25% - that’s just when she doubles down and the real fight begins.
Speaking of her spells, she can cast Flare, Scourge, Silencega, Shock and Syphon (drains target’s MP, restores own MP), while her technicks include Enrage, Mana Spring (reduces MP costs to 0) and Chain Magick. Also be wary of her normal attacks (a bolt of energy), as they deal around 500~ damage and inflict Disease, a status which must be removed immediately in this fight. Have Serums or Remedies ready to go. Last and not least… try to nab a Sagittarius Gem off of her during the fight, as it’s a common steal from Shemhazai, and you’re going to want several of these. Might as well take an easy one while you have the chance.