xxxHOLiC started off as with an episodic formula. Although it showed almost no exposition to the mystery behind the core premise, it managed to introduce most of the important characters and established strong emotional bonds between them. xxxHOLiC Kei, is where the wheels start rolling. Instead of the previous relaxed episodic format, this sequel drastically transforms itself with a deadlier, serious tone and arc format. The main characters finally face true danger, despair and challenges that were subtly warned from the prequel. There were a lot of stakes and sacrifices, nailing a good depth in the characters' development. There are still some comedic and relaxingbreathers in between to lighten up depressing mood. The pacing is perfect. Overall, it's a solid anime.

HOWEVER, there's still almost zero exposition on the main background. Along the series, it is obvious that the authors/writers are unwilling to reveal the core mystery and background of some characters, not exactly because it's too early (30+ episodes in), but because they haven't written or determined it yet. It's also closely connected to Tsubasa Chronicles which is shown in the later parts of manga and OVA, yet never really explained how they are connected. Plot holes are left unfilled for too long, and a decent completion would require unimaginable progress writing.

What a shame. xxxHOLiC has uniquely sharp character designs, elegant feminine traits and experienced drama writing. The anime also has amazing control of sound effect and music. But its overambitious crossover might be holding back the story too much. I enjoyed the anime so far, but I'm afraid its failure is inevitable.