All 3 Uses of

however

in

The Last Olympian

However, I see now that you are getting too old to be on the run without help.
Chpt 13 *

however = a word used to connect contrasting ideas as when using though, in spite of that, in contrast, nevertheless, etc.

Her weight, however, was enough to knock the drakon off the side of the building.
Chpt 16

The rest of the lobby, however, was jam-packed with wounded campers, Hunters, and satyrs.
Chpt 17

Definitions:

(1) (however as in: However, complications may...)
though (or another expression that connects contrasting ideas)

(Based on idea 1 we might not expect idea 2, but this is a way of saying that even though idea 1 exists, we still have idea 2. Synonyms include in spite of that, despite that, nevertheless, nonetheless, on the other hand, in contrastand but.)
(2) (however as in: However much she tried...)
to whatever degree (regardless of how much; or whatever unspecified amount)
(3) (however as in: However you do it, get it done!)
in whatever way