Before I get to the exciting bits of my crossover ship, we gotta know who they are and what their roles in their canons:
The Duke of Death and His Maid / Shinigami Bocchan to Kuro Maid
Walter is a canon character from the manga series, The Duke of Death and His Maid, written and illustrated by INOUE.
Walter is the secondborn and middle child out of three siblings; Viktor {The Duke} is the oldest and Viola is the youngest. Walter suffered from a inferiority complex and is sensitive to the number two and the word second as a reminder he is the secondborn or when he gets compared to Viktor. While Walter can be egocentric (In his goal), and mean (To Viktor only), Walter is also a gentleman and cared for his older brother in his own way; he used his goal to surpass his older brother and become the next head of their family one to find a way to help Viktor break his curse. In the series,it is shown that Walter is good at using a rifle, a fencer and at painting (Cut from the anime). He also knew how to drive a horse carriage. Walter eventually met his canon love interest,Daleth,the younger twin sister of the witch who cursed Viktor and empathize with her due to both being secondborns and ended up falling in love with her. Thanks to Daleth, Walter started to become less sensitive towards number two and the word second. While it wasn't shown in the manga, it was implied that Walter and Daleth got married; their draughter and Viktor's and Alice's daughter appeared in a manga chapter from The Duke of Death and His Maid official fanbook.Walter's Canon:
Konjiki No Gash!!
Suzume Mizuno (Known as Suzy Mizuno in in the official English manga and anime by Viz Media) is a canon character from the manga series, Konjiki No Gash!! (Zatch Bell! in the official English), written and illustrated by Makoto Raiku.
Suzume's Canon:
Suzume is a 14 year old classmate of the main character, Kiyomaro (Kiyo) Takamine. While she could be clumsy, ditzy, absentminded and gets sidetracked, Suzume is genuinely kind hearted, generous, and cheerful. She does her best in hard work and do anything to help a someone in need despite she'd make repeated mistakes. Suzume loves to draw faces on fruits to express her feelings.
Suzume have romantic feelings for Kiyomaro and once got jealous of her favorite idol, Megumi, due to the latter's friendship and parthership with Kiyomaro. She believed in Kiyomaro and attempted to shown kindness for him during his tough days in their middle school before he met Gash. As in Konjiki No Gash!! 2 (sequel to the original Konjiki No Gash!! manga), Suzume is now a 27 year old nurse and admitted she still wanted to become more than Kiyomaro's friend, but she does not want to be too pushy about the idea and it'd be difficult to deal with a long distance relationship with someone who likes to travel the world.