Judging by its size, strength, magical prowess, mana quality and the current situation, this possessed elephant is at least an A rank threat, capable of destroying an entire major city by itself. A strength shared by several high ranking monsters such as Behemoth, Goliath, High Vampire and more. 

Fortunately and unfortunately, the devil controlling the elephant got his eyes on me, but that can change. If the devil suddenly decides to go straight to where Charlotte is, the whole city of Estel will be destroyed, and with each passing second, as our clash goes on, I can't help but feel dreaded to the possibility that it's happening

As my great sword clash with the armour of the elephant, it's clear that this elephant is, indeed, stronger than the devil controlling it. I can tell that from the rusted armour, the worn out flesh, the old unhealed wound, and the unclean area in its body, this elephant was, indeed, being brought down by group of devils before being possessed by this devil

Furthermore, I can't help but feels like the unnatural dark mana emitted from the elephant is a sign of this elephant resisting whatever binding or controlling it. 

As the battle continues, the devil started to become more and more restless. The devil started to use multiple magic to help the elephant, in order to kill me quickly, alas, their compatibility is low, almost nonexistent if I am being honest

"You wretched elephant, do your job properly" [Devil]

He tried to charge the elephant's wind blast with his own dark mana, but the turbulence created simply become a disorganized mess, and as a result, some of the wind blast simply dissipated before even reaching me

"My my, is that all?" [Yuna]

"Don't you get cocky, you lowly human" [Devil]

Cocky? Maybe. I am simply amused by how the devil is behaving like a child, throwing tantrums whenever things didn't go his way. He's shaking his head, shouting stupid elephant multiple times, and this looks like the perfect opportunity for a single tide changing strike

"Ice age... Torrent... Gather around my blade" [Yuna]

Using a large amount of my ice and water magic, my great sword become ice cold, capable of freezing anything it touches. The torrent gathering at the grip and pommel of my great sword is imbued with high pressure and velocity raging water, as if a mini-tsunami compressed into a single point

"Take this!" [Yuna]

I throw my great sword into the devil's head, with it, the air become frigid cold, and a torrent of water being released propagate the great sword, causing the great sword to reach an astonishing speed.

"You thought I would just let you do that!" [Devil]

So the devil is still aware of my action, despite throwing his tantrums just now. The devil commanded the elephant to release a typhoon spell in order to counteract my great sword, and again, in his futile attempt to power-up the typhoon magic, he tried his best to mix the magic with his own mana, causing the spell to weaken

"You just don't learn, aren't you. Even Charlotte learns better than you're when she was nothing but a small child" [Yuna]

"Don't you dare compare me to the her..." [Devil]

He couldn't finish his sentence as the great sword pierces his head, causing it to freeze instantaneously and a stream of water from the sword finishes the job, causing the devil's head to shatter into pieces. Now, all that's left is to defeat this giant elephant