There was still time left with them as they were planning to stay the week so Ast decided that comprehending the elements would be a good idea, he also wanted to check out other stuff in the cave but he decided to save it for later.
"Anya we still have days before we go back, so we will try and comprehend the elements ok. So let me tell you me about lightning from what i know" said Ast and he started telling her all the things that might be relevant for her. His knowledge from Earth was vast and very useful he told Anya about how in nature lightning exists, how clouds formed of water are the cause of it. It was difficult to explain the concept of opposite charges so he tried explaining it by friction caused by the wind and so on. Anya asked a lot of questions and Ast answered patiently, he was surprised by how smart his cute sister was. Anya then tried to enter a meditative state near the pond and focused on the lightning essence inside her body.
'Now its time for me to begin my training' thought Ast. He quickly noticed that near the pond his thinking got sharper and he was getting various insights on light element. Ast has been researching on the light element whenever possible, he knew it would be difficult to get an element in the form that he wanted as the existance of darkness was different from what he thought. So he started asking himself what he knew about this element that he wanted and focused on trying to get the attributes of what should be his desired element. Ast didn't like direct confrontation so wanted to be able to sneak attack and something with stealth.
He suddenly thought about the shadows that we see daily. Shadows is a phenomenon created by light when light is unable to penetrate something a shadow is formed and the shadow itself is not completely devoid of light. A shadow has various regions some with more light and some very less, as one moves towards the center of the shadow the light element starts decreasing. Many such insights started appearing in his brain and Ast was in a state of enlightenment.
Anya was in the enlightenment state for a day, Ast had already given her a storage ring filled with food and other daily use stuff she ate her food and then again tried to comprehend the lightening element after two more days she got bored and started to practice her abilities. Ast woke up after 3 days his enlightenment had brought him a lot of ideas and he now knew the kid of element he wanted. For him to master the shadows he had to master the light. He had created a mind map on how to proceed and the next thing he had to learn was light absorption because that would open his path to shadows.