Indeed, bad...
Evil Dragon Lance had definitely lured that foolish young dragon into the area where lightning flashed and thunder roared, intentionally letting the young dragon be struck by lightning.
A young dragon that had never been struck by lightning couldn't withstand it like Evil Dragon Lance, who often flew into thunderous areas on purpose to use Thunder Tempering.
Although a Black Dragon by nature, after being struck by thunder numerous times, not only had it gained immunity to thunder, but it had also acquired the ability to control thunder. A creature that could control the Power of Thunder would grow up... to be at least a Lord-level monster.
There are Giant Dragons capable of mastering the Power of Thunder.
Thunder Dragons.