1:21 and 1:22 All of the verbs in this sentence have verbs in the present or imperfect, suggesting a lot of movement.
1:23 Mark puts the word "unclean" last in this clause, so it reads "there was in the syn. a man in spirit unclean." A bit of suspense. Also, Mark uses an aorist verb for "crying out" suggesting an abrupt change in the movement.
The word for unclean is "akathartos" as in the man needs a cathartic experience...
1.24 The phrase here in Greek that the unclean spirit uses is "What to you and to me." This is essentially what Jesus to his mother at Cana "What to me and to you." In other words, this is not a very kind way to talk!
The unc. spirit uses the PLURAL -- not the singular, even though the text only identifies the unc. spirit as one.
1.26 Interesting that even though the unclean Spirit obeys Jesus, it still causes problems on the way out!