“holy one.” This is an angel. Both angels and God’s holy people are called “holy ones” (see commentary on Daniel 7:18), which makes sense because they are both “holy ones.” The reader must be sensitive to the context to see if the text is referring to a person or an angel. Here in Daniel 8:13, the “holy one” is an angel.
“How long.” Although one angel asked this question to the other angel, it appears he did it for Daniel’s sake because the answer was given directly to Daniel (Dan. 8:14).