I’m a bit of an anime and manga fan. I’m no otaku by any stretch, but there are a few core series I really enjoy and one of those is the Guyver. When I first read the Numenera focus “Howls at the Moon” I expect I was supposed to jump straight to the idea of lycanthropy but reading about how the beast-within comes from an transdimensional source, the first place my mind went was Guyver.
For those unfamiliar with the series, without too many spoilers the Guyver is the story of Shō Fukamachi and how he comes across a ‘Guyver Unit’, a powerful alien weapon, an organic symbiote that vastly enhances the battle-capabilities of it’s host. By accident, Shō becomes bonded with the unit and is plunged into a fight for his life and the lives of those he cares about from the shadowy organisation that wishes to reclaim the lost unit.
The Guyver grants it’s host a huge range of abilities, such as enhances senses, vastly increased strength and agility, rapid healing and regeneration, sonic vibro-blades and gravity weapons, flight, lasers and even massive energy beam weaponry that can punch holes through mountains. The Guyver is an extremely powerful entity, way more powerful than “Howls at the Moon” would suggest, but perhaps some inspiration can be taken from it.
Like the mass of the beast-form in the focus, the Guyver too comes from a transdimensional space. After being bonded with a host, the unit disappears and weird lesions or marks appear on the host’s back. When the host summons the symbiote, the armour appears out of a transdimensional space and envelops them, turning them into the Guyver.
You could treat the focus in a similar way, perhaps even as similar unit - a symbiotic weapon that has bonded to the player’s character that they do not know how to control (at least at first). It adds some more Numenera flavour to what is otherwise a fairly run-of-the-mill werewolf-type focus. Of course, there are other aspects of the Guyver series which are just as appropriate, such as the Zoanoids - humans engineered to be able to transform into bio-weapons, powerful mutants with abilities similar to the Guyver in many respects.
Another way to make use of the Guyver is to make it an artefact. The unit could be discovered and perhaps activated. Perhaps it is damaged and destroys itself after a time (it’s been billions of years after all) but as an artefact or even as a powerful cypher you can make use of and play with the full range of the Guyver’s abilities and maybe even tie it into the lore and stories that make up the Guyver series. If you choose to do this, you will almost certainly want to count it as at least a level 10 artefact/cypher due to how powerful the Guyver unit is, unless you try and tone down it’s abilities.
In fact, beyond just the Guyver units themselves, the series has many, many cool, weird and really interesting things in it to mine for Numenera game inspirations, from zoanoid mutants, to explanations for humanities evolution, to powerful alien beings and organic weaponry. If you’ve never come across the Guyver before, I highly recommend you check it out, you can find some info on wikipedia and more on guyver.wikia.com.
The Guyver is a really enjoyable, highly violent anime full of weird and wonderful stuff that fits perfectly into the world of Numenera. To be really able to appreciate it it though, you should read the mangas or watch the series. Don’t bother with the live action films, they are terrible, though they have a certain power-rangers-esque cheesy appeal if you enjoy that kind of thing.
You can buy the new anime series on amazon here: Guyver - The Bioboosted Armor Collection [DVD]   or you can probably dig up episodes from the new series or the older OVA on YouTube. Finding the manga in English is harder (and the Japanese version extends far beyond what has currently been translated and published in English) but is well worth reading.