After taking a break during Round 3 due to the Ales Hemsky trade, the Senators were back at it in the fourth round, taking LW Filip Ahl. (Side note: how great will it be if Ahl plays in the AHL?) Ahl played this last year in Sweden, for the HV71 system. According to Elite Prospects, he played one game for the U18 team, 34 for the U20 team, and 15 games for the big club in the SHL.
Ahl finished as the 9th-ranked European skater in NHL Central Scouting's rankings. He was an honourable mention in TSN's rankings. Hockey's Future actually had him all the way up at 60th overall, while McKeen's had him at 63rd overall (paywall for both those sources). Looks like he's strong, good at puckhandling, and a relentless forechecker. He needs time to put on muscle and to continue to hone his skills, but playing in the SHL next year should help him.
Also, he's the son of Boo Ahl, which is an even more awesome name.