User blog comment:IamJakuhoRaikoben/Chapter 410: Memento Mori, Review./@comment-4449950-20141123060745/@comment-4449950-20141124015914


 * Erza wasn't proficient in her Magic though when she first got it... she just flung a heap of already present weapons at random with no skill using telepathy, and later picked up one of those weapon to continue fighting. There was no technique involved. She had to train to gain Requip and learn to control her Magic.
 * Wendy with notes is an example of needing to train.
 * Cana was given Fairy Glitter much like Gray was given IDSM, but she failed in her first casting as she noted that she didn't have enough power. Bluenote also stated that powerful Magic was useless in the hands of an inexperienced person.
 * Jellal learning Darkness Magic was as you said: Ultear was literally in his head controlling him, so that was more Ultear's talent with Jellal's body.
 * Lucy with Urano the first time had the knowledge of how to use the spell directly downloaded into her brain. The second time at the GMG she outright stated that she had been training with Gemini to try and use it again, and had therefore had practice.

As such, I don't see how Gray suddenly inheriting IDSM Glitter-style makes him a professional. As you said, the only other person to really pick up BS techniques without training is Natsu, and, funnily enough, I HATE it when Natsu does it too... so Gray doesn't get off the hook here for not making any sense at all.

See Nick's comment for my reply to Gray only landing a punch.