Dian Cecht is the name given to the drug created by Lugh. This drug is almost a narcotic, something that is both addictive and harmful to the body but that it can also give you superhuman concentration for a short time, making you feel like the world is moving in slow motion. Lugh spent several days compounding the drug in his workshop modeling it after what athletes used to take for doping in his old world.
This drug is made from mushrooms that Maha had obtained for him that are used by foreign tribes to invoke the gods, and they give an immense feeling of euphoria. In order to increase its medicinal effects to the utmost limit, Lugh processed it and added some ingredients to the mix, then he poured the resulting liquid into a syringe because it isn't as effective when taken orally. To use it, you need to press the syringe on your neck and inject the chemical.
Once done, your head will feel strangely cold, your vision will widen and eventually, everything around you will seem to move more slowly, and you will even feel almighty. This drug thanks with its superhuman concentration will give you a better understanding of your skills when used allowing you to evolve it by understanding and coming to grips with it.
The effects of this drug last thirteen minutes and twenty seconds. After that, you will be struck with severe nausea and fatigue. Your body will as heavy as lead, just like what happened to Lugh. However, the side effect of the drug, in Lugh's case, will disappear in less than a minute. The only way to prevent the brain from becoming addicted to that pleasure is to give it time, allowing you to use only one dose per day in the case of Lugh.
If you use the drug repeatedly, you would develop a resistance to it, which will decrease its effectiveness and make the effects wear off sooner, another reason why it should be used with caution.