Death Note 13: How to Read gives us an insight into the character of Quillsh Wammy, at least insofar as his author saw him.

The older man scores highly for versatility, talent, initiative/willingness to act, motivation and emotional strength.  Not far behind are his only slightly lesser scores for creativity, social skills and intelligence.  That he doesn't reach the topmost figure for creativity is a little surprising, given that Wammy made his fortune as an inventor.  The ultimate creator, one might think, this side of actual divinity.

We do get a hint of the kind of things that Wammy invented, when he turns up in the Death Note manga with belts containing panic buttons.  Not exactly Bond's Q, but in the ballpark.

As befits a man whose wealth and life has become devoted to raising children, his pet hate is 'dirty rooms'.  Presumably plenty of those at Wammy's House. I can't quite see the like of Beyond Birthday, Mello and Near running around with a duster.

This is an attribute taken to extreme levels in the Death Note TV drama, wherein guests are sprayed with disinfection at the door.  The interior of L's headquarters is kept pristine in its cleanliness, with Watari hurrying in to exchange L's shirt should a mere splash of food stain hit upon it.  In most tellings of the Death Note story, it's also inferred that Wammy is a fabulous cook.  At least there doesn't seem to be any travelling caterer providing all that confectionery for L that his handler regularly delivers.

Though it's nowhere stated that Wammy is an Englishman, it's implied in the location of his main orphanage for the training of gifted and talented orphans - Winchester, in England.  A further clue is given in his most favourite thing in the world - Earl Grey tea.

It's never truly explained how Watari managed to become such a crack marksman either.  His sharp-shooting is such that, in the Death Note manga and anime alike, he's able to fire a bullet which blasts a gun from the hand of Yotsuba's Kyosuke Higuchi, far below him on the ground. Wammy himself hovering over the scene in a helicopter at the time.

Nor do we learn where Quillsh Wammy acquired such skill in espionage, though he puts that to good use in Death Note, infiltrating various organizations to gain or deliver information.  Not least a gathering of Interpol.

Nevertheless he passed on all this knowledge, and the thinking/morality behind it, to the children in his care.   Maybe more clues to Watari's character reside in those he raised - how they turned out and what became of them.

Genius children taken from wherever they lived around the world and installed in Wammy's House, Winchester.  Here their 'special talents' were cultivated with a top class education, whereupon they were sent back out into the world to put those skills into practice.  All of these individuals were nurtured by Wammy - or at least had their upbringing and training overseen remotely by him, as warden Roger Ruvie took orders from above.

Each skilled Wammy kid set loose on the world was assigned a letter by Watari.   In L: Change the World, it's stated that this only occurs with the greatest, most intelligent of the Wammy's House outcrop.  Kujo is according stunned to belatedly realise that she was afforded the letter K.

Dotted across various adaptations of canon, we've practically got the entire alphabet in Wammy Letters.  With Watari himself indicated by the Letter W, only H, I, O, S and U are missing.  However, some known Wammy alumni never divulge their letters.  We don't, for example, know which Matt was assigned, despite him being third in the Wammy House rankings.  Nor yet do we know which letter Ryūzaki will take in the forthcoming movie Death Note 2016, assuming that he takes one at all.

Meanwhile, by the end of the manga/anime Death Note stories, Near interchangeably uses both N and L.  The latter earned post-Kira.  Thus giving an insight into the fact that letters can be taken from their peers by successful rivals/successors from the same Institution.  This is a system that Wammy himself must have set up.

Along with a code of ethics that apparently accounts for serial killers, abductors, biomedical scientists bent on mass destruction and the propensity of Wammy graduates to think it proper to die - or be killed - for want of a puzzle's solution. 

Chicago Comic and Entertainment Expo has just finished over in the Windy City.  It ran from March 18th-20th and Techaeris's Kyle Funk was there to catch what Viz Media had in store for fans of Death Note.

Turns out there's not much that we didn't already know or could guess.

In his piece VizMedia At C2E2 2016 #C2E22016, Funk confirmed that no add on to the Death Note manga is planned now or in the future.  That should answer the regular search terms leading people to this site, asking 'when will there be a new Death Note manga?' or 'is there a sequel to Death Note?'  Nope.  Sorry.

Mostly it seemed that Viz were in Chicago bigging up the Blu-Ray Death Note Omega Edition, which was recently released.  They showed a trailer demonstrating the difference in quality between the old bog standard anime and Blu-Ray.  Which is also on their YouTube Channel, so you may see it too, alongside an extended marketing clip unboxing the Death Note Blu-Ray Omega Edition, also by Viz Media.