Within the One-Octonion Brane-Bulk (OOB) framework, quarks are anchored in the positive quaternionic sector H+ (on-brane) with their deep ends extending into the negative quaternionic sector H- (off-brane). We show that color charge is the hyperbolic phase rotation in H-, related to the familiar circular U (1) phase by the Gudermannian map phi=gd (psi). The three color charges correspond to the three vertices of a 3, 7 triangle in the Klein quartic tiling, with color neutrality enforced by the exact Z7 closure 1+2+4=0 (mod 7) on Fano quadratic residues. Anticolor is the orientation reversal psi->-psi on the same Gudermannian sheet, which yields exact meson cancellation with no residual tension. The QCD string tension is derived from the flat GGRT result corrected by the Poincare disk conformal factor lambda (0) =2 at the center of the 3, 7 fundamental domain, giving sigmaQCD=Mᵣho²/pi, within 3% of the lattice value. The Luscher coefficient pi/12 follows from two transverse H- modes. The number of colors Nc=3 follows from Fano incidence (the order-3 quadratic-residue subgroup of Z*₇ labeling the 3, 7 heptagon vertices). Non-associativity of the ambient octonion structure is flagged as load-bearing throughout (steps: color-boost independence, Z7 neutrality, SU (3) ->G2 embedding). Predictions: P1 sigmaQCD=Mᵣho²/pi at leading order (2% above lattice; breakable on the choice of Regge input -- the asymptotic-slope input is overcorrected by the full lambda (0) =2 and must be reconciled in follow-up) ; P2 Nc=3 from Z7 Fano closure; P3 Luscher pi/12 from D-2=2 transverse H- modes; P4 (falsifiable) anticolor is psi->-psi, not the Fano complement k->7-k. Clinical cross-link: the H+ anchor / H- extension and the auxetic nu=-1 brane describe the Pipeline Embolization Device (PED) braid (wall anchor vs lumen-extending crossings), governed by the same lambda (0) =2 hyperbolic correction. Builds on Papers I (S7 split / G2 / Fano), CCLXIX (Klein quartic systolic fbulk), and CCXLVI (GGRT rotating-rod Regge relation). Method: fundamental insights B. D. J. ; mathematical formalization with Claude (Anthropic) ; B. D. J. author of record. Part of the One-Octonion Brane-Bulk Framework series. Anchor DOI: 10. 5281/zenodo. 19120873. Community: one-octonion-brane-bulk. Author: Bharathi Dasan Jagadeesan, M. D. , University of Minnesota. ORCID: 0000-0002-1143-941X.
Bharathi Jagadeesan (Sat,) studied this question.