Thanks to AQS for the scans.

Chapter 173: Konoka and Setsuna are in a greenhouse of Eva’s when Konoka sees a wounded bird and heals it. During the past seven days, Setsuna notes that Konoka has gotten better at her healing abilities. Konoka sees Setsuna is injured and despite Setsuna’s protests, Konoka activates her artifact and her clothing changes from a maid costume to one of her artifact costumes. Because Setsuna got the wound roughly 30-minutes earlier, Konoka’s artifact can’t heal it (it can only heal woulds up to three minutes old) so Konoka decides to suck on Setsuna’s injured finger. Setsuna backs away and Konoka laughs as she was teasing Setsuna, but states that her normal magic can heal the wound. She hasn’t gotten strong enough to heal Setsuna’s large injuries yet.

Konoka vows to continue to get stronger so that she can heal any kind of injury because if Asuna can get stronger, so can she. Setsuna is proud of Konoka and likes the influence Asuna is having. She asks about Konoka’s new costume and learns that a feature of the pactio card is that in addition to the costume on the card, one can register other costumes as well. Konoka states she’s going to see if there’s anyone else in need in healing while Setsuna isn’t sure about Konoka’s new costume (and somehow has changed from her school uniform to a maid costume in the blink of an eye without using her pactio card).

The two come upon a training session by Kotaro, Ku Fei, and Kaede. Ku has just split a huge boulder with her fist and Konoka is impressed. Setsuna and Kaede talk about Ku’s training while Ku talked with Kotaro and Konoka. Setsuna notices that Kotaro is stronger too, while Konoka notices his injuries. She wants to heal him, but he runs away and she can’t catch him. So, Konoka and Setsuna go to where Paru is. Paru has used her artifact to make four of herself to finish her manga, which she’s behind on.

Elsewhere, Yue and Nodoka report to Negi that they have completed 78-hours of magical studies, though Nodoka still has to finish the practical training part. Negi is impressed as are Setsuna and Konoka who have also arrived on the scene. As Setsuna wonders how Asuna is doing in her training, Asakura arrives with Sayo in tow while Chachamaru is bringing a protesting Chisame. Asakura has brought the meat for the barbecue.

As the party starts and people are eating (including Chisame’s mice, who praise her for her kindness), Chisame wonders if it is OK to start the party without Asuna. Setsuna agrees that it is worrying that she hasn’t shown up yet and so she, Negi, and Kotaro decide to go see if she’s OK. Asakura, Sayo, and Chisame are stunned when they hear about Asuna’s training in the icy region. Asakura figures that she is doing this because she loves Asuna, which causes Yue and Nodoka to spew. Nodoka isn’t sure but Asakura is having fun and continues to say this is love. She expands it by stating that all the girls are in the same boat — in love with Negi because otherwise why spend all this time at Eva’s castle.

As the girls protest, Chamo gets into the act, stating he has proof to back Asakura’s statement. He produces a love chart from a scroll, showing various girls with scores in different categories and a total score, which a shocked Yue snatches from Chamo. He produces more, stating the ability to measure affection is a gift of his. Yue and Ku grab those scrolls and piling them up, Chachamaru lasers them and causes them to burn. Konoka is bummed out about this, as is Paru and Asakura. Asakura decides to tease those who wanted the scrolls burned. It is after this teasing that they remember Asuna.

Setsuna, Negi, and Kotaro are making their way through a fog attempting to reach the summit, which is the only thing they haven’t explored yet. Coming out of the fog, they see Asuna near the tip of the summit with Eva and Chachazero behind. Eva tosses Asuna her pactio card, and in Asuna’s hand, it immediate becomes the giant sword, which she spins before planting in the ground. Having survived and proved Eva wrong, she demands to know if Eva has a problem. Eva doesn’t answer at first, which results in Asuna getting frustrated.

Eva asks why Asuna didn’t give up since there was no reason for her to go that far. Asuna states she doesn’t know about that, but concedes that Negi was part of the reason. She thinks about her conversations with Setsuna, Negi, and even Eva about their troubled past. She then pats Eva’s head and states that she did it to stay friends with everyone, so she couldn’t give up. She even confesses she doesn’t really dislike Eva that much. Eva isn’t amused and flips Asuna. Eva had given Asuna an out and she hadn’t taken it. She also didn’t remember (her past?) and so Eva reflect that the fool made it through as a fool.

With an evil grin, Eva throws off her coat and with an outfit that says “Master,” she states that she’ll personally train Negi and Asuna as her apprentices and make them worthy to serve her as “evil sub-bosses.” Asuna protests, but Eva isn’t done. Asuna must now wear black, goth-loli clothing. Asuna continues to protest with Eva hearing none of it while Negi, Setsuna, and Kotaro congratulate her.

In the real world at Shibuya, Ako, Makie, Yuuna are shopping for swimsuits and Yuuna is showing off her figure in a bikini. Ako and Makie are impressed with her chest size and hearing that she’s been drinking milk, the two rush off to order some mild from a nearby vendor.

Summary: So, just how did Setsuna instantly change from her school uniform to a maid costume?

As to the chapter itself, this merely sets the table to show that the girls are making progress in their training and that Asuna is now going to train with Negi and Eva. The final page is a filler omake and I suppose in addition to providing fanservice, is Akamatsu-sensei’s version of a comic strip.