Whole class lined up in the schoolyard. Sombra magically got rid of the grass, drawing two bare circles on a certain distance from each other and a line connecting them. Fire stood up into one of the circles. Sombra hopped to the other.
“Are you ready?” the King asked.
Lecturer cautiously nodded, placing his hooves to a more convenient position. Sombra spread his hooves apart, slightly lowering his head.
“The stage is Yours, Mr. Sense,” Sombra shouted smiling and staring at the hesitating lecturer.
Ten seconds passed. Suddenly, Fire's horn shined and three flashes of lightning started their way in the Sombra's direction. Right before his snout they all shattered hitting the quickly raised magical shield, which instantly disappeared.
“It is the invisible guard, which doesn't show itself until needed,” Sombra explained what happened to the students. Then he turned his head to Fire, “Try something else! I'm sure that your arsenal is not limited by the lightning,” he teased, grinning.
Fire shook his head from side to side. Well, if he wants to play... unicorn thought to himself, spreading hooves apart and slightly lowering his head. Fire's horn again flashed, firing green "fireflies" into the Sombra from different directions. Sombra quickly reacted to that, teleporting to avoid being surrounded. All "fireflies" changed direction still approaching now appeared King. But, to the students' surprise with the flash of the King's horn they started to hit each other until the last "firefly" reached Sombra and shattered hitting the invisible shield.
“Well, that's how I like it!” Sombra commented, smiling and returning into his circle, “Your lecturer used pure magic to control his fire projectiles. Quite dangerous spell to encounter if you don't know the suitable protection.
“Let's explain what happened. First, I used the teleportation spell to get the view of all projectiles. Mr. Sense was concentrating on keeping them in the air so he wasn't able to react. After that I used pretty complex protective spell with a combination of protection, manipulation, illusion and martial arts.
“As you noticed, your lecturer used pure magical energy. It's a spell from the school of martial arts, which mostly concentrates on the combination of different schools for combat purposes. With this knowledge I came up with a formula to take control over the magical energy and point projectiles into each other.
“Elaborating on it more... I noticed that your lecturer hesitates, he certainly feels anxious. This allowed me to take control of his magic by imitating his feelings using the illusion” — most students' faces looked confused — “Yeah, do not be surprised, school of illusion can do way more than that. So, then everything was pretty obvious. I used the knowledge of this spell to control the projectiles and let the last one hit my shield.”
“King deserves applause for such performance!” Fire shouted, being quite impressed by the sophisticated way Sombra decided to deal with his spell. Students erupted in their hooves beating the ground.
“Oh please, it wasn't so impressive,” Sombra answered, “it's far from being the limit of the skilled unicorn mages. Your lecturer hasn't even tried to trick me.”
Then Sombra asked Fire Sense to continue their duel. And after several good but trivial Sombra's defences Fire got quite heated up. He started to unleash different spells at Sombra. Fireballs, magical arrows, strong lightning strikes and even the dust storm. King gracefully deflected every spell directed into him, freezing the dust in the air and lowering it back to the trails. But that's where Fire caught Sombra and used a stunning spell on him. King even flinched in surprise, but deflected the spell directing it into the Fire. Lecturer fell unconscious. Sombra rapidly gazed at the fallen lecturer, realising what just happened.
“Oh. I didn't mean to—” he was a bit ashamed. Then Sombra turned his eyes to the shocked students, “Don't worry. He will be fine. After a day or two... he used a stunning spell and I had little to no time to react. My reflexes did everything for me, deflecting the spell into the caster. I haven't expected such manoeuvre from him, very few unicorns are able to use such non-trivial spell after combined series of attacking spells,” he was out of breath, but still looking calm, though a bit frustrated.
“I guess your lecture for today is over,” he approached the unconscious Fire, his horn flashed and the lecturer suddenly opened his eyes, quietly moaning. “Please, be so kind and help you lecturer to get to the hospital,” Sombra said, and then added, “here is a valuable lesson for you. Remember, magic opens a lot of possibilities for a unicorn, but you are responsible for its use. Always be careful... and sober,” with these words Sombra said goodbye to the students and trotted to the unicorn-guard waiting for him at the gates.
Lecture continued the next day. Fire still felt a bit dizzy, but it wasn't excuse to miss the class.
“I apologize. I made mistake yesterday and paid for it. Remember, magic is strong and dangerous, even for the user himself. Well, let's finish this. Yesterday King Sombra have shown you rather unusual protecting spells. For example, his last spell was a deflecting one, which reverses the target of the spell. If a unicorn is unprepared for defence, and I wasn't; then he gets hit by his very own spell. And, being honest, I haven't thought how strong my stunning spell is... My head still aches...
“But let's get back to the topic. For the effective defence you first have to learn the attacking spells. King Sombra demonstrated to you simplest magical shields and the grandmaster's custom protective spells. Let's not forget that school of protection is also widely used for the creation of the enchanted amulets and artifacts, which can save pony's life. They aren't very stable and hard in making, but our scientists are constantly working on making more reliable protective amulets.”