Lind studied the slips for an unknown amount of time. While the information was critical for increasing the respective Laws for the Inheritance of Creation or its legacies, the information he was seeking for was hinted at across them.
Refiners or Forgers wanting to make spirit tools could stumble across the secret or simply make items with the potential to have a spirit in the future. It was a rather common goal and many succeeded but inducing a spirit into a tool with that potential was a bit of a mystery.
Usually, like with Abby, the conditions had already been met and just needed a push. The beginning process, however, was a complete black box to even supreme experts.
In other words, various theories existed, but no one had a surefire path to pull it off in the Immortal Realm and below.
